This is the image supplied to us by the Zodiac Killer on the Phillips 66 Mount Diablo map on June 26th 1970. By placing the numbers 0, 3, 6 and 9 around the crosshairs, akin to a clock face, and instructing us that 0 is to be set to Mag. N, the Zodiac Killer is telling us that we have to travel a certain amount of degrees around the clock face from point zero (set to magnetic north, which was 17 degrees in 1970).

The Zodiac Killer realized that the information he provided in the Button letter was insufficient to discover where he was planning to set the bomb. He also realized it was insufficient to solve the 32-Symbol cipher. That is why he placed two crosshairs in his next communication on July 26th 1970. One of the crosshairs contained the radians value, while the other crosshairs contained the inches value. Zodiac wrote:

"P.S. The Mt. Diablo code concerns Radians + # inches along the radians".

It was that simple, all we had to do was place the first crosshairs (shown on the right) over a compass rose. The center of the little black circle with SFPD next to it, landed exactly at 246 degrees, which is 4 radians and magnetic north. That is the answer to the radians value. The target was SFPD.

The second crosshairs had the phrase "P.S. The Mt. Diablo code concerns Radians + # inches along the radians" written over it. Why would the Zodiac Killer place an arrow pointing before the inches value, if he didn't intend for us to place a number here? The answer could only ever be 5 inches, because using the Phillips 66 map scale of 6.4 miles to the inch, only 5 inches falls over San Francisco (4 & 6 falls into the sea).
The target of SFPD was therefore 4 radians and five inches from Mount Diablo. The target was the Southern Freeway by Ingleside Police Station, explained in greater detail here.

Whatever target the Zodiac Killer chose, it was extremely unlikely his radians and inches values would form whole numbers. This is why he gave us an estimate. On December 3rd 2020, David Oranchak, Sam Blake and Jarl Van Eycke solved the infamous 340 cipher after 51 years. On December 27th 2020, just twenty-four days later, Druzer (a regular contributor to both mainstream Zodiac forums) solved the 32-Symbol cipher. When four radians and five inches was placed into the 32-Symbol code with the word estimate, it married perfectly the three repeating ciphertext characters, giving us the complete solution to the code. The simplicity of this solution is its strength, because it doesn't require an explanation longer than the idea. I have zero doubt his solution is correct, which is why I am satisfied that the search for answers to the 32-Symbol cipher is over.

The Zodiac Killer mailed the Little List letter on July 26th 1970 setting out his search for "society offenders", but this lengthy communication was withheld from publication in the newspapers until October 12th 1970. Despite a comprehensive article in the San Francisco Chronicle on September 26th 1970 featuring the disappearance of Donna Lass from Lake Tahoe on September 6th 1970, the Zodiac Killer never raised his victim total of 13 from July 26th 1970 to October 5th 1970, when the 13-Hole postcard arrived. He never previously needed any prompting to falsely inflate his victim total in previous communications, yet a month after the abduction and likely murder of Donna Lass from the Sahara Tahoe Hotel & Casino, the Zodiac Killer kept his victim total static, suggesting at this juncture he was not claiming the young nurse as victim 14. That is, because he never murdered her. Besides, he would later retrospectively claim he had sought her as victim 12 in the March 22nd 1971 Pines card, while she was still present in San Francisco and working at the Letterman General Hospital by the Presidio.

Donna Lass would have been working as a nurse in the Presidio park in the relevant time period for her to be sought as victim 12. Bearing in mind that the Zodiac Killer was last seen entering the Presidio park after the murder of Paul Stine on October 11th 1969, he knew that by retrospectively claiming he had targetted Donna Lass in San Francisco before her eventual disappearance, it would carry more weight to his suggested involvement in her demise through the Pines card.

The punched hole in the top right corner of the Pines card was never a hint towards her burial location, because the Zodiac Killer had no idea where her body was located. The vague and cryptic phrases pasted on the Pines card were just designed to identify the name of Donna. When the "Sierra Club" was aligned over the Sierra Club of Clair Tappaan Lodge, the punched hole landed over the "Donner" of the Donner Memorial State Park. This was shown to be likely true when a similar pasted card, dubbed the Monticello card, arrived at the San Francisco Chronicle on July 13th 1971, again hinting at the identity of a murdered woman, that of Kathy Bilek. This time, the author pasted "Woods", "April" and "near Monticello" as a clue to her name. However, on this occasion, the sender would actually direct us to a burial site.

Buried in the Oak Hill Memorial Park & Cemetery in the Monticello neighborhood of San Jose was the resting place of Kathy Snoozy, claimed as a victim by the Zodiac Killer in the Dripping Pen card on November 8th 1969. She was the namesake of Kathy Bilek, who along with Deborah Furlong, were all victims of the real murderer, Karl Francis Werner. The Monticello card followed the exact pattern of the Pines card, in which the Zodiac Killer retrospectively claimed the April 11th 1971 murder of Kathy Bilek in the Villa Montalvo woods of Saratoga, by pasting "shought victim 21" on the card. He never murdered Kathy Bilek and he never murdered Donna Lass. When Karl Francis Werner was credited with two of Zodiac's previously claimed victims, that of Snoozy and Furlong, he doubled down and more, by adding Kathy Bilek retrospectively in a vain attempt to discredit the notion of Werner being responsible for all three. This belated tactic was used to claim Donna Lass as a victim also, with the Zodiac Killer selecting a time period between the 10 victims on April 20th 1970 and 12 victims on June 26th 1970, while Donna Lass was still working at the Letterman General Hospital for a large chunk of this time. He knew this would add credence to his claim of involvement in her disappearance and likely murder, particularly when he noticed the proximity of her profession to the Washington and Cherry intersection in Presidio Heights.

In fact, the Halloween card, Pines card and Monticello card may have all been retrospective communications, with the Halloween card incorporating the murders of Kathy Snoozy and Deborah Furlong into its design by the addition of two skeletons and the 4-TEEN on the card inner. The Zodiac Killer was only claiming four teenagers as murder victims by October 27th 1970, that of David Faraday, Betty Lou Jensen, Deborah Furlong and Kathy Snoozy. We know that the Zodiac Killer wasn't responsible for the three victims eventually attributed to Karl Francis Werner, despite him valiantly trying to retrospectively claim all three on numerous occasions. Therefore, we should place little credence to his suggestion of involvement in the untimely disappearance of Donna Lass through the Pines card, especially when he had every chance to elevate his victim total on October 5th 1970. This should give you pause for thought when the Zodiac Killer retrospectively inferred his involvement in Riverside on March 13th 1971, four and a half years after the fact.

Druzer and I have recently been working on the Mount Diablo map code solution, using the measurements of four radians and five inches supplied by the Little List letter crosshairs. Druzer came up with a solution to the 32-Symbol cipher that satisfied the three repeating ciphertext characters in the code, giving us an estimate of where the Zodiac Killer was threatening to "set his bomb". The target was the Southern Freeway alongside Ingleside Police Station, stated in a previous article as 4.03 radians (4 radians} and 4.84 inches (5 inches) from Mount Diablo, indicating that the Zodiac Killer was rounding off his values and giving us an estimate.

It has been stated on this site and elsewhere, that the 32 character code is unsolvable using conventional cipher techniques without the killer supplying us with a key. There are 29 unique characters within the code, making any solution practically unprovable. The solutions offered by using the 408 and 340 keys have produced less than convincing results, particularly when we consider that this code contains an "anchor" and "omega" symbol, not used in the 408 and 340 ciphers. Attempting to correlate the letters used in the code to written text in both the Button letter (June 26th 1970) and Little List letter (July 26th 1970) also produces negative results. Therefore, it could be argued, that a code containing 29 unique characters must have an alternative meaning, in accompaniment to the code solution of "estimate:four radians and five inches".

The Zodiac Killer gave us an estimate of 4 radians, but the actual figure (shown above) was 4.084 radians. That is, 4.084 multiplied by one radian value (57.3 degrees) to equal 234 degrees. When we add in the magnetic north which Zodiac instructed us to do (17 degrees in 1970), we get 251 degrees and the location of Ingleside Police Station. Could the 32 character code contain the value of 234 degrees, which once set to magnetic north, now identified the exact location of Ingleside Police Station? If we resort to basic numerology where A=1, B=2, C=3 etc, and add up the values of the alphabetical characters in the Zodiac Killer's 32 character code, we arrive at a total of 234 (or 234 degrees). When set to magnetic north, it gives us the value of 251 degrees, which when subtended from the peak of Mount Diablo passes directly over Ingleside Police Station and the Southern Freeway. "The map (set to 17 degrees magnetic north) coupled with the code of 234 will tell you where the bomb is set".

On July 26th 1970, the Zodiac Killer mailed the Little List letter with the important clues to the Mount Diablo mystery, stating "PS. The Mt. Diablo Code concerns Radians & # inches along the radians". The answer would be about radians and inches. With the northern section of the map crosshairs positioned at zero and to be set to magnetic north, the Zodiac Killer gave us the value of 4 radians and magnetic north (246 degrees) by the placement of the bold, black circle within the first crosshairs on the Little List letter.

The target was the San Francisco Police Department at Ingleside (SFPD). The second set of crosshairs on the Little List letter contained the hashtag (number sign) in the phrase above, with an arrow placed underneath, beckoning us to insert a number before inches. Only 4 radians and magnetic north, coupled with 5 inches could ever fall over San Francisco, constrained by its land mass. No other values can meet the requirement of targetting SFPD. To an overall accuracy in excess of 98%, the location of the bomb was to be set on the embankment of the Southern Freeway just 274 feet from Ingleside Police Station. For the full story, read The Answer to the Mount Diablo Code.

My solution to the 32-Symbol code in the above article did not marry up the ciphertext to the plaintext adequately, however, Druzer, an invaluable contributor to both Zodiac Killer forums, supplied a solution that married up the three repeating ciphertext characters with corresponding plaintext characters. His solution took "PS. The Mt. Diablo Code concerns Radians & # inches along the radians". into "four radians and five inches" that satisfied the requirement of the Zodiac Killer's Mount Diablo code. This would ultimately provide us with 24 of the plaintext characters for the solution, leaving us 8 ciphertext characters to decode. Druzer came up with the answer, but how was this achieved?     

The problem that materialized, was where to place "four radians and five inches" within the 32-Symbol array. We needed an entry point. The clue had to exist within the ciphertext characters themselves. Two of the most notable ciphertext characters were the Anchor and Omega symbols (the latter of which had never been used before), so possibly it was this symbol that held the key of where to insert "four radians and five inches".

The Omega symbol can be written two ways (shown on the left), with a quick search on Wikipedia revealing information on the radian per second. The radian per second (symbol: rad⋅s−1 or rad/s) is the SI unit of angular velocity, commonly denoted by the Greek letter ω (omega). The radian per second is also the SI unit of angular frequency. The radian per second is defined as the change in the orientation of an object, in radians, every second. 

Using this as the entry point in our ciphertext characters, the word "radians" was placed at the beginning of the Omega sign in the code, hoping that the 24 plaintext characters of "four radians and five inches" would travel to the end of the code. Inserting "four" before "radians", It fell into the code seamlessly (as shown below).

Now we can add in the three plaintext characters represented by O, C and ∆ to the three repeating ciphertext characters in the first section of the code, like so.

Ingleside Police Station is actually 4.03 radians (4 radians} and 4.84 inches (5 inches) from Mount Diablo, so the Zodiac Killer was rounding off his values and giving us an estimate. As can be seen in the above diagram, the word "estimate" fits perfectly into the first eight characters of the code, giving us the final answer to the 32-Symbol code of "estimate: four radians and five inches". The Zodiac Killer was informing us that the answer to the Mount Diablo code of "four radians and five inches" was just an estimate to the location of the bomb at Ingleside Police Station (SFPD). The Merriam-Webster dictionary defines "estimate" as a rough or approximate calculation, which is exactly what it is.

In respect to the Mount Diablo code, the Zodiac Killer gave us two clues to where his bomb was to be set, in the form of two crosshairs on July 26th 1970. The first crosshairs contained a bold, black circle positioned at 4 radians and magnetic north around its circumference. Next to this circle, the Zodiac Killer placed SFPD=0, indicating the target was a San Francisco Police Department. The second crosshairs were overwritten with the wording "P.S. The Mt. Diablo code concerns Radians + # inches along the radians". The hashtag (recognized as a number sign) was positioned above a pointing arrow, beckoning us to insert a number value before inches. The answer is five inches, because this is the only value that falls over San Francisco from Mount Diablo using the map scale of 6.4 miles to the inch. The bomb was to be set alongside Ingleside Police Station, on an embankment bordering the Southern Freeway. For further explanation in simplified form, please visit here, or for more extensive coverage read the article The Answer to the Mount Diablo Code.

Footnote: Ordinarily radians would be measured counter-clockwise, but the Zodiac Killer gave us crosshairs superimposed over Mount Diablo with an arrow pointer set in the north facing position, "to be set to Mag. N". He allocated it a zero position, with a 3, 6 and 9 in the form of a clock face around its circumference. This was to instruct us to travel clockwise around the circumference of the crosshairs in this instance. Which is why it was no fluke that the bold, black circle fell exactly at 4 radians and magnetic north.

The Blast Estimate of Zodiac (Part Two)

The Zodiac Killer often responded to the newspaper articles written about him, usually in close proximity to their release. The Dripping Pen card had likely been purchased subsequent to the morning of October 25th 1969 in response to the last San Francisco Chronicle article by Paul Avery. If the 340 character cipher had been specifically designed to compliment this card, then it too was crafted subsequent to October 25th 1969. As the title attributed to this communication suggests, this greeting card featured a dripping pen on its front face, accompanied by the wording "Sorry I haven't written, but I just washed my pen". The Avery article read "Zodiac struck last on October 11 when he gunned down cab-driver Paul Stine on Washington Street in Presidio Heights. He revealed himself the killer in a letter sent to the Chronicle three days later. Since then he has remained silent".

Bearing in mind the wording "since then he has remained silent", it could be argued that the chosen card of "Sorry I haven't written" was purposefully selected in response to this article - and therefore chosen by the Zodiac Killer after October 25th 1969. The paragraph in the newspaper article also referred to Washington Street, thereby completing the phrase on the card "but I just washed my pen". The last observation is probably a little far-fetched, and heavily reliant on the Zodiac Killer being able to find a greeting card apologizing for being silent, as well as containing a word related to Washington Street. Extremely unlikely, but not impossible.

Then, the day before the November 9th 1969 'Bus Bomb' letter, came the newspaper article detailing the attempted murder of Richmond school teacher, Daniel Williams. Somebody claiming to be the Zodiac Killer made sadistic phone calls spanning October 23rd 1969 and November 2nd 1969, and culminating in a soft drink in his refrigerator being laced with arsenic. This failed murder plot may have inspired the Zodiac Killer (if the poisoner) to insinuate his continued pursuit of Daniel Williams, by stating "I though you would nead a good laugh before you hear the bad news" and "up to the end of Oct I have killed 7 people". On November 12th 1969, the San Francisco Chronicle released information on the Dripping Pen card and Bus Bomb letter under the banner of I've Killed Seven, The Zodiac Claims.

This newspaper article featured the observations of an individual with respect to the X's on the Bus Bomb crosshairs (see right). This observation was suggested in the article The Promise of Murder on Line 5.

I believe the person who initially made this suggestion was almost certainly correct. However, when I floated this idea on November 23rd 2020, I was fully aware of the Mount Diablo map and crosshairs accompanying the Button letter, which was mailed to the San Francisco Chronicle on June 26th 1970. I positioned the Bus Bomb crosshairs over Mount Diablo and rotated them slightly clockwise, so that a line drawn from the peak of Mount Diablo through four of the five X's passed directly over Lake Berryessa, Vallejo (where two attacks occurred), San Francisco and San Jose.

When we consider that this person made the observation on November 12th 1969, seven-and-a-half months before the Mount Diablo map was mailed by the Zodiac Killer (on June 26th 1970), the interpretation by this individual is extremely intriguing.  

The five cross marks cannot directly pinpoint the five claimed attacks in Benicia, Vallejo, Lake Berryessa, Presidio Heights and San Jose by superimposing them over a map. If you arrange any two X's over Lake Herman Road and Blue Rock Springs, the other three X's will never fall over Lake Berryessa, Presidio Heights and San Jose. The only way it is possible, is by placing the crosshairs over Mount Diablo (rotated clockwise} and drawing lines through the X's on the circumference. But this still leaves the 9 o' clock line unaccounted for. This is where Daniel Williams, the Richmond school teacher comes in. The sadistic phone caller to Daniel Williams may have wanted to target schoolchildren at the Richmond school where he worked (Salesian High School falls over the line drawn through the 9 o' clock position}. This is covered in the article A Killer on Line Five.

The newspaper article stated "Zodiac's letter contained five cross marks which possibly refer to attacks. Comparing these markings against a map, one interpretation that can be drawn is that they pinpoint Lake Berryessa, Vallejo (where two attacks occurred}, San Francisco and San Jose". It was effectively saying that five cross marks could pinpoint four locations (identifying Vallejo as the location where two attacks occurred). Despite classifying Lake Herman Road as Vallejo, the tight grouping of the first two attacks on the map would allow the observer to reach the same conclusion as shown in the above map. After all, this person didn't say "Zodiac's letter contained five cross marks which possibly refer to five attacks".

The Zodiac Killer likely chose Mount Diablo because of its use when surveying land boundaries in Northern California, with the summit used as the "initial point". Was it possible that the person behind the interpretation on November 12th 1969 had correctly identified Mount Diablo as the "initial point" to center the crosshairs over, by using the same reasoning as Zodiac? The Zodiac Killer himself classified Lake Herman Road and Blue Rock Springs under the banner of Vallejo (evident on Bryan Hartnell's car door), so when he provided five cross marks to signify four general locations, he was deliberately leaving the 9 o' clock line as a puzzle to the location of his next attack. He employed exactly the same technique, when substituting the X around the crosshairs with a bold, black circle around the circumference of the crosshairs on July 26th 1970, again designed to pinpoint the location of his next attack. On this occasion, it would be a school bus traveling on the Southern Freeway by Ingleside Police Station, positioned at 4 radians and magnetic north.   

After watching the very educational and insightful presentation of Let's Crack Zodiac (Part Four) by Dave Oranchak for the National Cryptologic Museum, the section about the X's positioned around the Bus Bomb crosshairs sparked a fresh interest. Dave Oranchak is correct when he identifies the difficulty regarding scale when overlaying the crosshairs over a map. The Zodiac Killer overlayed his crosshairs over Mount Diablo as part of the Button letter on June 26th 1970, which he followed up with a further clue in the Little List letter on July 26th 1970. The Zodiac Killer explicitly stated that the crosshairs were to be set to Magnetic North (17 degrees in 1970). Therefore, it wasn't particularly surprising that the center of the black circle around the circumference of the first crosshairs on the Little List letter, fell exactly at 4 radians when set to Magnetic North, ultimately identifying Ingleside Police Station as the focus for the bomb.

Two overlays were used to great effect in the June 26th and July 26th communications. It is with little doubt that the Bus Bomb crosshairs were designed to pinpoint locations as well. However, as Dave Oranchak pointed out, the scaling of such an operation is likely to lead to inaccuracy. Therefore, we have to treat the crosshairs on the Bus Bomb letter as a guide. Only a day earlier, the Zodiac Killer had listed his murder count on the Dripping Pen card, mailed to the San Francisco Chronicle on November 8th 1969. He chronologically listed the murders he was claiming by use of months, writing "Des, July, Aug, Sept, Oct = 7".

We know the Zodiac Killer had murdered five victims at Lake Herman Road, Blue Rock Springs, Lake Berryessa and Presidio Heights, but he added in the murders of Kathy Snoozy and Deborah Furlong in San Jose on August 3rd 1969. To this point, the Zodiac Killer had listed his victims, but always left us dangling with the promise of more murders. Would it be all that unusual if the Zodiac Killer again pinpointed these seven victims the following day by use of X's around the circumference of his crosshairs, just like he pinpointed 4 radians and Magnetic North around the circumference of his crosshairs in the Little List letter on July 26th 1970 - with both crosshairs overlayed over Mount Diablo. But in true Zodiac style, the promise of another location in which he would soon murder. If this were the case, we would expect one X on the circumference of the Bus Bomb crosshairs to be unknown.              

To a reasonable degree of accuracy, line [1] falls over Lake Berryessa and the murder victim Cecelia Shepard. Line [2] passes directly over Lake Herman Road and Blue Rock Springs, accounting for David Faraday, Betty Lou Jensen and Darlene Ferrin. Line [3] passes over Presidio Heights and the murder of Paul Stine. Line [4] passes over San Jose and the murders of Kathy Snoozy & Deborah Furlong. These were the locations of his seven victims which he had claimed just a day earlier. One line remains unknown. This line passes over Walnut Creek (where Elaine Davis was abducted from on December 1st 1969, and eventually murdered), as well as Richmond and San Rafael. Had the Zodiac Killer deliberately created this X on the 9 o'clock position as a teaser to his next destination of murder? Next to the bottom right quadrant of his crosshairs on the Bus Bomb letter, he wrote "Be sure to print the part I marked out on page 3 or I shall do my thing". Considering this section of text was placed next to the crosshairs with the X's, was his "thing" going to occur somewhere in the vicinity of Walnut Creek, Richmond or San Rafael, along the unknown line? As far as we know, no murders can be connected to the Zodiac Killer over the next few months in these locations, making you wonder whether this was just another threat that didn't materialize. Or it was simply just a game he was playing.  

FOLLOW UP ARTICLE: A KILLER ON LINE FIVE  

The Zodiac Killer mailed the Button letter on June 26th 1970 promising us that the "The Map coupled with this code will tell you where the bomb is set". Thirty days later, on July 26th 1970, he would give us the near-full answer to the 32-Symbol code, which only required the number 5 added to it (Radians and 5 inches along the radians). He also drew the dark, black circle around the circumference of a second set of crosshairs to provide the exact angle we had to travel away from Mount Diablo.  However, when he constructed the Button letter, he was of the opinion that he had provided us with enough information to solve the conundrum of where the bomb was set. This in itself was a massive clue when you consider the code had only three repeating characters. The introduction to the Button letter stated "I have become very upset with the people of San Fran Bay Area. They have not complied with my wishes for them to wear some nice Zodiac buttons. I promised to punish them by anilating a full School Buss. But now school is out for the summer, so I punished them in another way. I shot a man sitting in a parked car with a .38". It is clear that this introduction has nothing to do with the code, and in no way can be manufactured to explain the meaning behind the 29 unique characters contained with the 32-Symbol code. Therefore, the solution to the 32-Symbol code was expected of us (by Zodiac) using only what he added to the Phillips 66 map. This appears impossible - but it is not. 

Obviously, the following has only been worked out in hindsight of knowing the answer to the Mount Diablo code. This is why the Zodiac Killer gave us the two crosshairs with the answers in the Little List letter a month later - he knew that the clues he gave us on the Phillips 66 map were scarce to say the least. The Zodiac Killer gave us very little when he drew the crosshairs on the Phillips 66 map, yet he still expected us to use this to solve the 32-Symbol code. This should have been the biggest clue of them all. There is absolutely no way anybody can individually decode 29 unique characters in the 32-Symbol code by using what the Zodiac Killer drew on the map, but the crosshairs on the Mount Diablo map can be used to identify where particular words began on the 32-Symbol code, from which we can then start filling in the blanks - much like the Harden's identified the double symbols on the 408 cipher to identify "kill", therefore beginning the process of decoding. Once you get your foot in the door, eventually the whole cipher starts peeling open like an orange. This exact same process had to be adopted to unravel the 32-Symbol code using the crosshairs on the Phillips 66 map. The key was devilishly simple, but extremely unlikely to have been unearthed without the benefit of hindsight. 

To unearth the position of the bomb we have to travel a certain distance around the circumference of the circle of the crosshairs, set to Magnetic North (17 degrees in 1970). Then we had to travel a certain distance away from the summit of Mount Diablo (marked as position X by the Zodiac) from that degree point. The first thing we had to discover was his likely target area. The map was of San Francisco & Vicinity, with all the Zodiac Killer's previous letters and bomb threats focused towards San Francisco and the police. Therefore, the Zodiac Killer likely expected us to explore this avenue first. But before we do that, let's explore the limited characters contained by the crosshairs above.

To find the angle around the crosshairs we have to consider that any number of degrees could fall over San Francisco from its north to south border, with no way of determining this figure from the information supplied. So, we have to look for a way of measuring an angle around the circumference of the crosshairs where only one figure is possible for the answer. This lay in the radian, because only 4 radians and magnetic north could fall inside San Francisco (beginning from his arrow pointer, set to magnetic north and traveling around the clock face he provided). No other radian value could land inside San Francisco. We now have to focus on the diagram above. Radians would travel around the circumference of the crosshairs, so let us take a punt that the repeating C in the 32-Symbol code was representative of crosshairs/circumference, and therefore the radians that traveled around them. These would be the first two words inserted into the 32-Symbol code below. 

There are two other symbols or characters inside the crosshairs on the Phillips 66 map. The first one is the X symbol, deliberately accommodated by the Zodiac Killer by not fully completing the intersecting lines of his crosshairs. He could easily have just drawn normal crosshairs over Mount Diablo and everybody would have known this was his beginning point, yet he carefully left this area free to insert the letter X. This alphabetic letter can be found in the 32-Symbol code, so let us again assume that this is the starting point for another word. The only other character visible inside the crosshairs on the Phillips 66 map is the (in part) filled-in red triangle. We will take the same approach we did with the X symbol, and assume that the filled-in red triangle is represented on the 32-Symbol code by the filled-in black triangle (again beginning a word). The black triangle is often used to depict a mountain. We now have the C, X and black triangle in the 32-Symbol code, all of which should be the beginning of words.

Just like the degrees argument above, we know that by using miles as a measurement, any number of miles from Mount Diablo to San Francisco can fall within its eastern and western borders. Therefore, the answer cannot be in miles. But using the map code of 6.4 miles to the inch only one figure of inches can fall inside the land mass of San Francisco - and that figure is five. We also know that if the black triangle in the 32-Symbol code begins a word, then that word can only be 6 letters in length before the next word kicks in with the X character. Miles doesn't fit this criteria, but inches does. We now have effectively inserted three words into our 32-Symbol code (shown below).

We know that only 5 inches from Mount Diablo lands in San Francisco, so it's now easy to insert the figure 5 before inches. We cannot insert the word "five" because "radians five radians" doesn't read fluently. Once we have added the figure 5 before inches, it's easy to add "and" into the sentence to read "radians and 5 inches". Whether the reversed letter F represented 5 is impossible to tell. The rest of the solution is now pretty easy to guess. We are left with Radians and 5 inches _ _ _ _ _ _ _ _ radians. Once a line is drawn radiating away from Mount Diablo at 4 radians and magnetic north, we then have to travel 5 inches along the 4th radian value. This gives us the final two words of the 32-Symbol code of "along the".

We now have the full answer of Radians and 5 inches along the radians. If this reasoning had been used between June 26th 1970 and July 26th 1970 and given to the police prior to the arrival of the Little List letter, the suggested solution to the 32-Symbol code would probably have been accepted when the Zodiac Killer wrote "PS. The Mt. Diablo Code concerns Radians and # inches along the radians" at the foot of the July 26th letter. Unfortunately it wasn't.

The Zodiac Killer used exactly the same concept in his 13-Symbol code by highlighting three 8's by circling them (representative of Jesus Christ, resurrection, infinity and a new beginning). These again were found to begin each element of the solution "Fk, I'm crackproof", which when inserted into the code was infinite and circular in nature. The first 8 began FK, the second 8 began IM, and the third 8 began CRACKPROOF. The letters K and M were already present in the code as an aid. Just like the 32-Symbol code, the Zodiac Killer gave us the answer to the 13-Symbol code on October 5th 1970, seemingly frustrated, or had become aware that his clues were too difficult and scarce in nature. In both the 13-Symbol and 32-Symbol codes, the Zodiac Killer created anchor points where each word was to begin. Once the month of October 1970 had rolled on by, the Zodiac Killer would never elaborate on the workings of his ciphers ever again.

The Mount Diablo Map and Code Solution    The Codes of Zodiac Never Required an External Solve

The first three San Francisco Police officers killed in the line of duty in 1970 were Eric Zelms, murdered when he lost control of his firearm when investigating a pawn shop robbery on January 1st. The second was Brian McDonnell on February 16th 1970, who suffered devastating and sadly fatal injuries seven weeks later, when a bomb packed with fence staples exploded on an outside ledge of Park Police Station in the Upper Haight neighborhood. The third was Richard Radetich on June 19th 1970 at 5:25 am, who was gunned down by three shots from a .38 caliber revolver at point blank range through the driver side window of his vehicle while in the process of serving a parking ticket. He was sat in his police car near 643 Waller Street, San Francisco in the Lower Haight District.

The Zodiac Killer didn't personally name any of them, but referred to them indirectly when he stated "two cops pulled a goof", "I hope you do not think that I was the one who wiped out that blue meannie with a bomb at the cop station" and "I shot a man sitting in a parked car with a .38". Additonally, all three communications carried the message of his bomb-making. 

The April 20th 1970 communication not only threatened that there was "more glory in killing a cop", but provided us with imagery that showed he had already set aside a location for his school bus bomb. The Zodiac Killer had specifically chosen a bus route traveling from north to south with a steep embankment on the right and the sun rising to the east. When deciding where to place his bus bomb, one would think the killer would be drawing from experience with regards to the best location. The diagram of the bus bomb location in the April 20th 1970 letter would eventually be discovered to be the embankment directly opposite Ingleside Police Station and alongside the parking lot of the City College of San Francisco. The addition of two crosshairs on the July 26th 1970 "Little List" letter would expand on the Button letter (a month earlier), and show to a 98% accuracy that the target was the Southern Freeway embankment opposite Ingleside Police Station - which was also a bus route. This would effectively kill two birds with one stone for the Zodiac Killer. Was the Zodiac Killer familiar with the City College of San Francisco, having worked at this location or even studied there?   

The Zodiac Killer certainly wanted to paint a picture he was familiar with law enforcement practices, giving rise to the notion he may have worked at, or attended the City College of San Francisco, where he could possibly have crossed paths with Richard Radetich, who attended a criminology course prior to becoming a police officer with the San Francisco Police Department. Greg Corrales was a legendary San Francisco Police officer who knew Richard Radetich and stated that "Richard, who had recently been assigned to Traffic, regularly stopped at Ingleside Police Station to say hello to his former colleagues. He glowed when he talked about his new baby girl and his wife. He was an outstanding police officer and a devoted family man". It is clear that Richard Radetich took criminology classes at the City College of San Francisco before being assigned to duties at Ingleside Police Station just 850 feet east of the college. Richard Radetich had formerly been a student at Balboa High School, 585 meters to the east of Ingleside Police Station. This aligns Sgt. Richard Radetich at the City College of San Francisco (and likely parking lot) studying criminology, with the bus bomb designated for the eastern edge of the parking lot on an embankment, alongside a bus route traveling north to south (with the sun rising to the east), only 274 feet from Ingleside Police Station (where Radetich had worked) - and subsequently - the Mount Diablo code pinpointing this location. The Mount Diablo code letter would also indirectly reference the murder of Sgt. Richard Radetich on June 19th 1970.

It is highly unlikely that the Zodiac Killer was responsible for the murder of Sgt. Richard Radetich, with the previous observations just a simple case of unfortunate coincidences, but it still leaves pause for thought when you consider the location of the bomb had been earmarked in a letter two months in advance of his murder, on April 20th 1970. A letter that highlighted the bombing of Park Police Station and the murder of Brian McDonnell, with the claim that "It just wouldn't doo to move in on someone else's teritory". So, did the Zodiac Killer move to a territory slightly south of Park Police Station, the clue to which lay in the attached bus bomb diagram?

On October 12th 1970, Paul Avery of the San Francisco Chronicle wrote an article concerning the Zodiac Killer's latest two communications, notably the July 26th 1970 "Mikado" letter and the October 5th 1970 "13 Hole" postcard. The Zodiac Killer may have used much of this newspaper article to choose and fashion the October 27th 1970 Halloween card, including a continuance of The Mikado theme. The Zodiac Killer wasn't averse to plagiarising reading material for his communications, with the Halloween card fashioned not only from the Tim Holt comic book, but possibly crafted using the Paul Avery article as his inspiration.

The October 12th 1970 newspaper article was entitled Gilbert and Sullivan Clue to Zodiac, thereby giving the Bay Area murderer about two weeks to find the appropriate reply in the form of a Halloween card beginning "I feel it in my bones you ache to know my name. And so I'll clue you in". The newspaper article detailed "Sheriff's detective sergeant Kenneth Narlow who had fruitlessly followed up another 900 tips as to Zodiac's identity since Sept 27, 1969". So finding a Halloween card teasing us again with his name and offering to clue us in, appeared like the ideal card in response.

In the first column of the article, Paul Avery wrote "Homicide detectives who've been hunting Zodiac for nearly two years frankly admit he is much an enigma now as he was on Dec. 20, 1968, when he chalked up his first two victims". Those two victims were teenagers David Faraday and Betty Lou Jensen. The Zodiac Killer decided to chalk his victims on the Halloween card in white marker pen above the head of the inner skeleton and beneath its feet, in the form of 4-TEEN and what could be Zodiac Victims Fourteen or Zodiac Fourteen.

The author of the card could have written 14 (similar to the outer skeleton hand) or fourteen, but intentionally separated it to 4-TEEN. David Faraday and Betty Lou Jensen were two of Zodiac's confirmed victims, but he had also claimed Deborah Furlong and Kathy Snoozy by the addition of "Aug" in the Dripping Pen card on November 8th 1969, who were both teenagers. The Zodiac Killer had claimed 4-TEENS as victims, hence why he altered fourteen to 4-TEEN, to incorporate them into his running victim total. The addition of four dots (little marks) around ZVF or ZF possibly created for a similar reason. It can be noted that Paul Avery also referred to David Faraday and Betty Lou Jensen in the article as teenagers, but he hyphenated the word into teen-agers, just like Zodiac did with his running teenager total of 4-TEEN.

The majority of the newspaper article focused on the July 26th 1970 "Mikado" letter and the search for potential Ko-Ko's, The Lord High Executioner featured prominantly in the July 26th 1970 (Little List) letter. The Mikado Act One Part 5a  As some day it may happen was performed by Ko-Ko of the town of Titipu. This led investigators to consider the possibility of a Zodiac Killer who played Ko-Ko in his student days. But where was The Mikado and Ko-Ko in the Halloween card? Perhaps the investigators could have searched the knothole in the tree.

The original card came with one eye peeking from the knothole in the tree, in which the Zodiac Killer circled the words "Peek-a-Boo you are doomed". But notice how "Peek-a-Boo" and "you are doomed" are deliberately separated.

The Mikado is a two-part comic opera by Gilbert and Sullivan, which opened to the paying public on March 14th 1885 and was hugely successful, running for 672 performances at the Savoy Theatre in London. However, this wasn't the only version of the opera from that time period, In 1888, Ed J. Smith wrote a stage parody of The Mikado called The Capitalist; or, The City of Fort Worth to encourage capital investment in Fort Worth, Texas. In this version, Peek-A-Boo is listed as one of the three sisters and wards of Kokonut (The Lord High Executionist).

The Mikado original featured Peep-Bo: A ward of Ko-Ko and sister of Yum-Yum and Pitti-Sing. Peep-Bo is the British version of Peek-a-Boo. Peekaboo (also spelled peek-a-boo) is a form of play primarily played with an infant. To play, one player hides their face, pops back into the view of the other, and says Peekaboo!, sometimes followed by I see you! There are many variations: for example, where trees are involved, "Hiding behind that tree!" is sometimes added.

Peep-Bo can also be reversed to Bo-Peep, believed to originate from the 16th century practice of concealment, before reappearing to startle or surprise. See here. Little Bo Peep is a popular English nursery rhyme The earliest record of this rhyme is in a manuscript of around 1805, which contains only the first verse. There are references to a children's game called "Bo-Peep", from the 16th century, including one in Shakespeare's King Lear (Act I Scene iv), but little evidence that the rhyme existed. The additional verses are first recorded in the earliest printed version in a version of Gammer Gurton's Garland or The Nursery Parnassus in 1810.

The phrase "to play bo peep" was in use from the 14th century to refer to the punishment of being stood in a pillory. For example, in 1364, an ale-wife, Alice Causton, was convicted of giving short measure, for which crime she had to "play bo pepe thorowe a pillery". Andrew Boorde uses the same phrase in 1542, "And evyll bakers, the which doth nat make good breade of whete, but wyl myngle other corne with whete, or do nat order and seson hit, gyving good wegght, I would they myghte play bo pepe throwe a pyllery". Taken from Wikipedia. The skeleton on the card inner also appeared to be hanging in the form of punishment, as if placed in a pillory. I suppose the "punishment must fit the crime".

Bearing in mind the newspaper article of Paul Avery, was the Halloween card drawing on the search for Ko-Ko's by its design of inserting Peek-a-Boo around the knothole of the trunk, with the eye "hiding behind that tree"? Was the chalked-up victim count of 4-TEEN above the pilloried skeleton denoting the running total of fourteen, including four teen-agers? The newspaper article of Gilbert and Sullivan Clue to Zodiac may have spawned the choice of Halloween card with the introduction of "I feel it in my bones you ache to know my name. And so I'll clue you in". But did it inspire anything else?

The problem with solving the Zodiac Killer's 32 Symbol cipher and Phillips 66 Map code, is a failure to follow the instructions given by the killer in the June 26th 1970 letter and its follow up on July 26th 1970. The Zodiac Killer stated "The map coupled with this code will tell you where the bomb is set.  You have untill next Fall to dig it up". This tells us that the solution to the 32 symbol cipher will not supply us with the exact position of the supposed bomb. Any solution to this 32 character code pinpointing the exact position of the bomb will be incorrect, because this can only be realized by coupling it with the map. Therefore, the position of the bomb to be set, was a combination of both code and map.

In his following letter he stated "P.S. The Mt. Diablo code concerns Radians + # inches along the radians". This tells you that the code is about radians and inches but not necessarily the entire solution. Any solution to the position of the bomb that doesn't use radians and inches (as implicitly stated by the killer) will be wrong. The 32 symbol code supplied the inches component to the answer, hence the hashtag before inches, along with the arrow beneath, instructing us to insert a value here. This isn't rocket science - the hashtag is widely recognized as a number sign, so by placing this immediately before the word "inches", the Zodiac Killer is telling us to insert a number before inches. The only way to find a bomb in Northern California using his instructions, is to travel a set amount of radians around his crosshairs, and then subtend a set amount of inches from it. In this case, a number of radians around Mount Diablo and a number of inches from it. Placing a hashtag and arrow before the word "inches", is rather a giveaway that a number value should precede it. Even the map code was 6.4 miles to the inch. Any solution that gives us the answer in degrees or miles is wrong, because "The Mt. Diablo code concerns Radians + # inches along the radians". We need to follow his instructions. This is why any theory of crime scene locations being chosen because they are separated by a radian or near radian value, is wrong also. The whole premise of the June 26th 1970 letter was to discover the location of his bomb, not measure angles between crime scenes or any other object we choose to construct or imagine

The Zodiac Killer gave us crosshairs superimposed over Mount Diablo with an arrow pointer set in the north facing position, "to be set to Mag. N". He allocated it a zero position, with a 3, 6 and 9 in the form of a clock face around its circumference. This was to instruct us to travel clockwise around the circumference of the crosshairs, to be set at 17 degrees (which was the magnetic north value in 1970). We had to travel a set amount of radians around his crosshairs over Mount Diablo, in addition to this value of 17 degrees. So, we are looking for a set amount of inches and a set amount of radians. The Zodiac Killer was incapable of keeping secrets and resisting putting pen to paper, so just one month later he gave us the answer, when the July 26th 1970 letter arrived at the San Francisco Chronicle.          

Never done before or since by the Zodiac Killer, he drew a big fat zero around the circumference of his crosshairs with SFPD alongside it. This represented the San Francisco Police Department. This bold, black circle sat at 246.2 degrees, which is 4 radians and magnetic north. This was the radian component of "The Mt. Diablo code concerns Radians + # inches along the radians". The answer was 4 radians. All we had to do now was find the "inches" value.

The Zodiac Killer mailed virtually every correspondence to the San Francisco Chronicle, describing the makeup of his bomb on November 9th 1969. He followed this up with a diagram of a school bus and photoelectric cells on April 20th 1970, referencing the murder of San Francisco police officer Brian McDonnell on February 16th 1970, who suffered devastating and sadly fatal injuries two months earlier, when a bomb packed with fence staples exploded on an outside ledge of Park Police Station in the Upper Haight neighborhood of San Francisco. The Zodiac wrote about the "blast" he was going to have when he mailed the Dragon card on April 28th 1970. All of these communications directed towards the San Francisco Chronicle indicating he was constructing a bomb, with the SFPD attribution totaling zero adorning many. Therefore, it's pretty obvious that placing SFPD around the circumference of his crosshairs, next to a big fat zero and set to a value of 4 radians and magnetic north (4 X 57.3 + 17), indicates that the target for the bomb is San Francisco - or more specifically - the San Francisco Police Department. When the above crosshairs are set over Mount Diablo, we now have to travel 4 radians and magnetic north from the peak of the mountain. Let us now find the inches value to be inserted into "Radians and # inches along the radians".

We actually don't have to look hard to find the answer. The land mass and geography of San Francisco is such, that only 5 inches can fall over it. Using the map scale of 6.4 miles to the inch, anything less than 5 inches, and anything more than 5 inches, doesn't fall inside San Francisco. Therefore, there is only one answer. The same applies to the radians value. Anything more or less than 4 radians and magnetic north (such as 5 radians and magnetic north, or 3 radians and magnetic north), doesn't fall inside the geography of San Francisco. A bomb threat on San Francisco (hence SFPD=0), can only be 4 radians and magnetic north, and 5 inches along that radian value. The choice of words by the Zodiac Killer when he wrote "Radians and # inches along the radians". were chosen carefully. We were instructed to find "radians", and an amount of "inches" along the amount of "radians" we found. Once we found the radians value, we would travel 5 inches along that radian. The complete answer to where the bomb was to be set, was "4 Radians and 5 inches along the radian". But this wasn't the answer to the 32 symbol cipher, because the Zodiac Killer explicitly stated "The map coupled with this code will tell you where the bomb is set". The answer to the code was Radians and 5 inches along the radians (consisting of 32 characters). This is why he capitalized the first Radians and began it on a separate line. The answer to the map was the superimposed crosshairs of the bold, black circle sitting at 246 degrees (4 radians and magnetic north). The two "coupled" together gave us the full answer. 

The map scale is 6.4 miles to the inch. This gives us a distance of 6.4 multiplied by 5 (inches). Therefore, the bomb was to be set at 4 radians and magnetic north, and 32 miles from the peak of Mount Diablo. The only San Francisco Police Department that comes anywhere close is Ingleside Police Station. This San Francisco Police Department sits at 30.96 miles from the peak of Mount Diablo (4.84 inches). It also sits at 248 degrees from the peak of Mount Diablo (4.03 radians).

The Zodiac Killer gave us a rough guide of 4 radians and magnetic north, and 5 inches. If he had given us the exact measurement, it would have been 4.03 radians and 4.84 inches, He was clearly giving us an approximate measurement. Since Ingleside Police Station was the only San Francisco Police Department anywhere close to these measurements, it's fairly obvious this was his target. The Zodiac Killer's distance in miles was 96.8% accurate. His angular accuracy in degrees was 99.3%.   

The Zodiac Killer was targeting Ingleside Police Station for his bomb, but clearly he wasn't going to start digging a hole on the lawn of Ingleside Police Station. The Zodiac Killer also threatened to blow up a school bus on April 20th 1970, in which he drew us a diagram with a steep embankment on the right, with the sun rising to the east. This would suggest we should be looking for a bus route traveling from north to south (where the sun rises to the east in the morning), with a steep embankment to the right of the bus, where the Zodiac Killer can lay his photoelectric cells and conceal his bomb. He also has to access that roadway from a position of anonymity, with his vehicle parked at the top of the embankment in relative seclusion. What are the odds of that location being the exact closest portion of road to Ingleside Police Station, meeting all the criteria above. This would satisfy the drawing on the April 20th 1970 letter and the target of SFPD (Ingleside Police Station). The Zodiac Killer could metaphorically kill two birds with one stone.

So let us travel just 274 feet from Ingleside Police Station to the nearest section of road heading north to south.

Again, what are the chances that the area highlighted by the red rectangle would mimic exactly his bomb diagram of a school bus and embankment, as drawn in the April 20th 1970 letter. Not only that, but this would have been a school bus route in 1970. Children from the northern and eastern areas of San Francisco would use the school bus to reach St Thomas More Catholic School at 50 Thomas More Way. There is even a bus route road sign 38 feet from the proposed location of the bomb (whether it existed in 1970 I don't know). So, let us drop down to the exact position of the red rectangle and take a closer look.

All the Zodiac Killer had to do to access the embankment, was to access the parking lot of the City College of San Francisco and drive to its eastern edge - and at night - in relative anonymity to the police station, dig the bomb into the embankment. It is highly unlikely that the Zodiac Killer ever intended to plant a bomb, but this location fits all the criteria of targeting both a San Francisco Police Department and a school bus at the same time. It achieves his objective of targeting school children for maximum terror, and achieves his objective of "rubbing the pigs nozes in their booboos". The location of the bomb not only matches the diagram from April 20th 1970, but satisfies the criteria of the Mount Diablo map and code to an overall accuracy of 98%. The 32 character cipher is also answered. The Zodiac Killer had no intention of laying this bomb, but it was the threat that mattered most of all. The Zodiac Killer knew that the clues he provided us with on June 26th 1970 were inadequate in cracking the bomb location and code, so he gave us these additional clues in the Little List letter on July 26th 1970, one month later.

# Radian values are normally measured in a counter-clockwise direction, but the positioning of the bold, black circle at 246 degrees (4 radians and magnetic north), along with the north facing arrow pointer, the addition of the clock face set at zero, and the instructions to "set to Mag. N.", appears to indicate the Zodiac Killer measured his radians from the north position clockwise. In effect, he was multiplying the radian value of 57.3 by a factor of 4, set to magnetic north of 17 degrees (246.2).
Additional reading: The Anchor Points in the 32 and 13 Character Codes.    

On April 20th 1970 the Zodiac Killer mailed a letter to the San Francisco Chronicle with three key components. [1] The Zodiac Killer stated "I hope you do not think that I was the one who wiped out that blue meannie with a bomb at the cop station.  Even though I talked about killing school children with one. It just wouldn't doo to move in on someone else's teritory". The Zodiac Killer was referencing the murder of San Francisco police officer Brian McDonnell on February 16th 1970, who suffered devastating and sadly fatal injuries two months earlier, when a bomb packed with fence staples exploded on an outside ledge of Park Police Station in the Upper Haight neighborhood. He continued [2] "But there is more glory in killing a cop than a cid because a cop can shoot back". [3] The Bay Area murderer also included a bus bomb diagram, with a school bus traveling south in the morning and the sun rising to the east. The bomb was positioned on a steep embankment.

It therefore shouldn't be any surprise that his next letter on June 26th 1970 contained all three of these components in its design: [1] He claimed he had set a bomb by Ingleside Police Station, [2] claimed his "glory" by insinuating his involvement in the shooting death of Officer Richard Radetich and [3] his bus bomb diagram matched perfectly the bomb to be set by Ingleside Police Station. In addition, the history of Officer Richard Radetich is pertinent to the location of the bomb. 

In the June 26th 1970 Button letter he stated "The Map coupled with the code will tell you where the bomb is set*. It is clear the bomb was to be set in San Francisco, the target for the majority of his communications and ire toward police. The code provided the inches (5 to be exact) and the map was to provide the radians, to be set at Mag. N (magnetic north) from his zero point clockwise. This was plainly evident when he provided the extra two clues in the following Little List letter on July 26th 1970.

The first clue was the first set of crosshairs, where he placed the bold, black circle at 4 radians and magnetic north (246 degrees} around the circumference. This was to be placed over the Mount Diablo map of San Francisco & Vicinity, centered over Mount Diablo to give us the radian value. The second clue was therefore the solution to the 32 symbol cipher containing the inches - where he placed the hashtag and arrow for the number 5 to be inserted. Therefore we had to travel approximately 5 inches along a line subtended at 246 degrees from Mount Diablo. This is why he used the phrase "The map coupled with the code will tell you where the bomb is set". The image on the right overlayed on the map gave us the radians or degrees, coupled with the code which only contained the inches value. The bomb was to be set close to Ingleside Police Station, which to a high degree of accuracy fell extremely close to 4 radians and magnetic north, and five inches from Mount Diablo. The inches subtended from Mount Diablo at 246 degrees couldn't be more or less than 5, because a bomb (set at 4 or 6 inches) would have fell into the sea on the east and west side of San Francisco. The bold, black circle on the right, should be evident that the target was to be the San Francisco Police Department.

I have placed the number 5 into place, giving us the answer to the code of "Radians and 5 inches along the radians" (which is 32 letters in length). The positioning of the bomb had to meet certain criteria. With a high degree of accuracy, Ingleside Police Station was situated 4 radians and magnetic north, and 5 inches from Mount Diablo. Even a line subtended from Mount Diablo passing over the neighborhood of Ingleside in San Francisco, when considered alongside the addition of SFPD=0, should have told us that the target for the bomb was likely the San Francisco Police Department in Ingleside. No other police station in San Francisco comes close to 4 radians and magnetic north, and 5 inches along the radians. The next task was looking for the exact location for the bomb to be buried. It most likely would have been set in the vicinity of the police station, just distant enough not to be observed.
 
The bus bomb diagram in the April 20th 1970 letter (shown above) depicted a school bus traveling from north to south in the morning, next to a steep embankment, with the sun rising to the east. This location is just 230 feet from Ingleside Police Station. School buses traveling from the northern and eastern edge of San Francisco to St.Thomas More Catholic School would travel the Southern Freeway, passing only 210 feet from Ingleside Police Station. From this location the bus would be traveling south in the morning to begin classes for the day, the sun would be rising from the east, and this location has a steep embankment mirroring exactly his bus bomb diagram of April 20th 1970. This portion of the Southern Freeway is flanked by the parking lot at the City College of San Francisco. This parking lot is the ideal location to access the embankment without parking on the freeway.        

Every criteria has now been met. The school bus, the route of the school bus on a freeway, the southerly direction, the steep embankment, the target of SFPD (San Francisco Police Department) and the 4 radians and magnetic north coupled with the code of 5 inches. The 32 character code wasn't the complete solution, because the Zodiac Killer explicitly stated "the map coupled with the code will tell you where the bomb is set". The code contained the inches by way of "Radians and 5 inches along the radians", to be coupled with the map which contained the 4 radians and Mag. N (246.2 degrees). A bomb set here would have had maximum impact, striking a school bus as Zodiac had promised, but more importantly, right under the noses of the San Francisco Police Department for acute embarrassment. However, there may be one other factor to contemplate, when we consider the reference to Officer Richard Radetich in the June 26th 1970 letter, containing the Mount Diablo code. The map and code took us to a location exactly bisecting Ingleside Police Station and the City College of San Francisco.

Sgt Richard P. Radetich (25) was murdered on June 19th at 5:25 am, gunned down by three shots from a .38 caliber revolver at point blank range through the driver side window of his vehicle while in the process of serving a parking ticket. He was sat in his police car near 643 Waller Street, San Francisco in the Lower Haight District. Numerous magazine and newspaper articles covered his brutal execution and gave a background of the young officer's life. Officer Richard Radetich attended Balboa High School in San Francisco, before attending a criminology course at the City College of San Francisco with the express intention of joining the San Francisco Police Department. His first assignment was at Ingleside Police Station, before transferring to the Accident Investigation Bureau.  

The Zodiac Killer was an avid reader of the newspapers and had previously mentioned the murder of Officer Brian McDonnell on February 16th 1970, killed by a bomb placed on the ledge of Park Police Station. In the June 26th 1970 Button letter, the Zodiac Killer claimed his involvement in the murder of Richard Radetich, while giving us a location for the bomb that bisected Ingleside Police Station and the City College of San Francisco - two of the places Officer Richard Radetich attended prior to his murder, while serving in the Accident Investigation Bureau. Had the Zodiac Killer read about the murder of the young officer, and cynically positioned his claimed bomb on the Mount Diablo map at a location pertinent to Officer Radetich's life. Exactly between Ingleside Police Station and the City College of San Francisco? And the design of the bus bomb diagram was just a fortunate coincidence to this location.

The April 20th 1970 bus bomb diagram was penned two months before the murder of Officer Richard Radetich, so if this location was deliberately earmarked well in advance of his murder, it is unlikely the Zodiac Killer chose it because of the history of the young officer in the newspapers subsequent to June 19th 1970. But it wouldn't rule out the deliberate targeting of an officer connected in some fashion to Ingleside Police Station or an advance knowledge of their history, however implausible this may seem. Whatever the case, the primary focus of Ingleside Police Station and an attack on an officer, because "there is more glory in killing a cop" is a viable one. The location of a proposed bomb on the Southern Freeway by Ingleside Police Station, matches both the Mount Diablo map and code of 4 radians set to magnetic north, and 5 inches along the 4th radian. The location also matches perfectly the bus bomb diagram within the April 20th 1970 letter. These still stand, irrespective of any connection to Officer Richard Radetich, which may have no bearing whatsoever. 

The Ingleside Police District encompasses the area south of Cesar Chavez Street to the San Mateo County line and west from Highway 101 to Faxon Avenue. It is  home to the San Francisco City College campus and many diverse residential neighborhoods including Sherwood Forest, Mt. Davidson, Glen Park-Sunnyside, Diamond Heights, Bernal Heights, Upper Noe, Mission Corridor, the Excelsior and St. Francis Wood, St. Mary's Park, Visitacion Valley, Precita Park, Cayuga, Outer Mission and Holly Park.

THE 340 CIPHER WAS CRACKED ON DECEMBER 3RD 2020 BY DAVE ORANCHAK, SAM BLAKE AND JARL VAN EYCKE, SO THIS EARLIER ARTICLE SHOULD BE VIEWED IN RESPECT TO RECENT DEVELOPMENTS.

The one thing we can confidently state about the Zodiac Killer was his propensity to engage with the newspapers when prompted. This was demonstrated throughout his letter-writing campaign, but particularly evident when he responded to Jack E. Stiltz on August 4th 1969 and Chief of Police Martin Lee on November 9th 1969. This was clearly a tactic of the police to engage the Zodiac Killer in communication rather than murder and hopefully ascertain more knowledge of their nemesis through his wording. This was exemplified by Dr. D.C.B. Marsh on October 22nd 1969, when an article entitled Cipher Expert Dares Zodiac to Tell Name was presented to the Zodiac Killer through the San Francisco Examiner, explicitly aimed at prodding his ego. It was hoped that the murderer of five would take up the challenge rather than shy away from the dare or produce something meaningless in response.

Many people have stated that the 408 Cipher was not the hardest cryptogram to solve, despite the fact that many claiming it was an easy cipher could not have cracked it. Hindsight is a wonderful thing. What the 408 Cipher told us, whether the Zodiac Killer just read a book or manual on cipher-solving, is that he had enough knowledge to comprehend that a code comprising of 13 characters was incapable of supplying a provable solution without a key. In other words, if you cannot prove the origin and voracity of the key, anything you produce will fail to meet a burden of proof. The composition and structure of the article below was likely designed to play on the narcissistic traits of the Zodiac Killer and encourage him, at least in part, to rise to the challenge. Responding to the dare in the San Francisco Examiner with absolutely nothing but 13 meaningless characters and no answer whatsoever, is a rather pointless exercise - and could be construed as a failure on Zodiac's part.

The newspaper article pressed the Zodiac Killer no less than four times, implying to do so would lead to his capture under the guise of dare, truth and honesty. I sincerely doubt anybody expected the Bay Area murderer to supply us his full name in the code, to which he would later supply the key or answer. Therefore, the question is, how could the Zodiac satisfy the challenge without giving us his forename and surname? The simple answer is, he could supply us his initials without any fear it would jeopardize his freedom. The important quote in the article is "Zodiac has not done this, because to tell the complete truth in relation to his name - in cipher code - would lead to his capture". Dr. D.C.B. Marsh must have known that a Zodiac Killer providing something 'in relation to his name', left the door open to the murderer supplying us his initials. Six months later, the Zodiac Killer opened his April 20th 1970 communication with "This is the Zodiac speaking. By the way have you cracked the last cipher I sent you. My name is...." 

The Zodiac Killer knew that a code of 13 was unsolvable, which is why he would eventually give us the answer in a later communication in 1970. The prompt was "Zodiac has not done this, because to tell the complete truth in relation to his name - in cipher code - would lead to his capture". The answer was "This is the Zodiac speaking. By the way have you cracked the last cipher I sent you. My name is Fk, I'm crackproof". In other words, my initials are FK and you can't solve the last cipher I sent you because I'm crackproof - although I've held my end of the bargain by supplying something in relation to my name. The Zodiac Killer satisfies his ego and the challenge by Dr. D.C.B. Marsh and the San Francisco Examiner. The answer was supplied in the October 5th 1970 '13 Hole' Postcard - but would we recognise it when we saw it?

The June 26th 1970 Mount Diablo code and map were no different, except this time the Zodiac Killer supplied us the exact answer to the 32 symbol cipher after only 30 days. The Phillips 66 map contained the Zodiac crosshairs as part of the puzzle, so it wasn't that surprising that the answer came embedded within two crosshairs on the July 26th 1970 'Little List' letter. The first crosshairs with the bold circle supplied the radians, and the second crosshairs with the hashtag and arrow supplied the inches. The only two components required to locate the supposed bomb location.

The end of the Little List Letter read "PS. The Mt. Diablo Code concerns Radians and # inches along the radians". The Z32 was the easiest code to crack because the Zodiac Killer just gave us the answer above - the code concerned "Radians and inches along the radians". Why make it any more complicated than it has to be? A code of 29 unique symbols within a total of 32 characters is simply not solvable without a key - and there is insufficient wording on the 13 Hole Postcard, Halloween Card or Los Angeles Letter written in plain English to formulate any such key. The Z32 is even worse than giving us the English alphabet of 26 letters, replacing M with A, W with B and H with C and saying "now solve it". There is no transposition key present in the remaining three communications from October 5th 1970 to March 13th 1971, so if the Zodiac Killer was to be consistent in his inability to resist revealing his deeds, then the only realistic alternative is he gave us all the answers instead.      

Not only did the Zodiac Killer give us the answer to the 32 character code on a separate line, he capitalized the first "Radians" to effectively tell us this was the beginning of the solution (he didn't capitalize the second "radians", so why the first). You need look no further than the Paul Stine police report to notice that the hashtag symbol is used in conjunction with a number. Why insert a hashtag - and an arrow pointing to the hashtag - if you are not suggesting something should be inserted here?

The symbol # is most commonly known as the number sign, The symbol is described as the "number" character in an 1853 treatise on bookkeeping, and its double meaning is described in a bookkeeping text from 1880. The instruction manual of the Blickensderfer model 5 typewriter (c. 1896) appears to refer to the symbol as the "number mark". Some early-20th-century U.S. sources refer to it as the "number sign", although this could also refer to the numero sign. A 1917 manual distinguishes between two uses of the sign: "number (written before a figure)"; and "pounds (written after a figure)". Mainstream use in the United States is as follows: when it prefixes a number, it is read as "number", as in "a #2 pencil" (indicating "a number-two pencil"). The one exception is with the # key on a phone, which is always referred to as the "pound key" or "pound". Thus instructions to dial an extension such as #77 are always read as "pound seven seven". Wikipedia.

The Zodiac Killer by use of an arrow pointer underneath the hashtag, was telling us to replace the hashtag with a number value. The Mount Diablo map scale was 6.4 miles to the inch, so it is probably unsurprising that the "Mt Diablo code would concern inches". In this instance, I have placed the number 5 into place, giving us the answer to the code of "Radians and 5 inches along the radians" (which is 32 letters in length). The reason for 5 inches is self explanatory, because 4 or 6 inches from Mount Diablo to San Francisco would fall into the sea on the east and west side. The San Francisco element will be covered shortly. The Zodiac Killer also gave us a second set of crosshairs (shown below).

This was the first time the Zodiac Killer had ever placed an accentuated zero within his crosshairs alongside the acronym SFPD. This had to be the second clue to the location of the bomb. The hashtag and arrow signified the value of inches required, so this had to signify the radian value. By some massive stroke of luck (almost beyond belief), the bold, black accentuated circle fell over 246 degrees on a compass rose - which is 4 radians and magnetic north (17 degrees in 1970). Therefore, the target of his bomb must have been 4 radians and magnetic north, and 5 inches along the radians. 

All Zodiac's bomb threats were focused towards the San Francisco Chronicle and San Francisco Police Department, so placing this bomb location alongside the acronym SFPD should tell us that the threat was most likely focused toward a police station. By another massive stroke of luck, when we travel 4 radians and 5 inches from Mount Diablo, the target area for the bomb lies right by Ingleside Police Station. Allowing for a degree of flexibility of less than 1%, by the Zodiac Killer rounding off his radians and inches, along with the black circle diameter, no other San Francisco police station comes close. However, we need to find a location where a school bus would be traveling from north to south (with the sun to the east), that has an embankment on the right side (as displayed on the April 20th 1970 bomb diagram), with easy and covert access to that embankment, and within a few hundred feet from Ingleside Police Station. The Zodiac Killer certainly wouldn't have wanted to attract attention by parking on the road itself, but by accessing the incline from a secondary location - likely at the top of the embankment - he could achieve this task in relative anonymity. Fortunately for us, that location sits only 230 feet from Ingleside Police Station. The perfect location for the Zodiac Killer to target a school bus and thumb his nose at the San Francisco Police Department, with covert access to the top of the embankment via the car park of San Francisco City College.     

The 32 character code wasn't the complete solution, because the Zodiac Killer explicitly stated "the map coupled with the code will tell you where the bomb is set". The code contained the inches by way of "Radians and 5 inches along the radians", to be coupled with the map which contained the 4 radians and Mag. N (246.2 degrees). A bomb set here would have had maximum impact, striking a school bus as Zodiac had promised, but more importantly, right under the noses of the San Francisco Police Department for acute embarrassment.        

In addition to the Fk I'm crackproof clue, the 13 Hole Postcard was punched in the style of a 'Dick Tracy' code with a "red crucifix decoder". What are the chances that if we arrange the 13 holes into the shape of a cross and place them over the midsection of the 340 cipher both horizontally and vertically, they would reveal the wording "paradice" and "slaves"? Then, what are the chances that the Zodiac Killer would write "paradice" and "slaves" in his next communication in a cross formation on the card, accompanied by "sorry no cipher" in a cross formation on the inside of the Halloween Card envelope? - totaling three cross formations - but supposedly, all created for absolutely no reason whatsoever in just two communications. Isn't it more believable they were created for purpose. The Zodiac Killer could easily have written "sorry no cipher" just the once, but deliberately fashioned it this way to tell us that the 340 character cipher was not a cipher after all. It was simply a design of "paradice" and "slaves" as exhibited by the Halloween Card. Throw in a few bigrams, pivots and 'corrected sixth line', and hopefully it will look convincing. 

All these clues from the back end of the Little List Letter to the Halloween Card giving us the literal answer to the Z340, Z32 and Z13 in "paradice" and "slaves", "Radians and 5 inches along the radians".and "Fk, I'm crackproof".  The following observations will go into a little more detail on the Z13 code.

On January 29th 1970, the Yellow Cab Company put up a thousand dollar reward for any information leading to the arrest of the Zodiac Killer. In addition, the Teamsters Union which represents the Yellow Cab Company were reported in the San Francisco Chronicle to be considering offering a further reward on February 8th 1970 in the case of Paul Stine and Charles Jarman (another taxicab murder victim). The April 20th 1970 letter gave us the code and was immediately followed by "I am mildly cerous as to how much money you have on my head now". The October 5th 1970 postcard gave us the possible solution of "Fk, I'm crackproof" and was immediately followed by "What is the price tag now". These are the only two communications in which the Zodiac Killer asked the police the price of his capture. These two communications not only had a code and an answer that fitted the code, but both were followed by the exact same question. When the Zodiac Killer was designing his 13 Hole Postcard, it is very likely he had at his disposal a copy of his original April 20th 1970 letter, or the San Francisco Chronicle newspaper cutting below, to which he was now supplying the answer. This may have been the trigger that influenced him to repeat the phrase "how much money you have on my head now" into the very similar "What is the price tag now". The Zodiac Killer, in essence, had inadvertently bound both communications together through phraseology, as well as code and solution.   

The Zodiac Killer introduction would now give us his name (albeit his initials) in absence of his full name. It would also read fluently as a sentence, as follows: "This is the Zodiac speaking. By the way have you cracked the last cipher I sent you? My name is Fk, I'm crackproof". Nobody realistically believed he was going to supply his full name, but this way he satisfies the promise in a restricted format. Two communications mailed nearly six months apart, with a solution that satisfies the code, as well as a satisfactory introduction to the code - and both followed by the same question.    

The three 8's (representing Jesus Christ in gematria), along with the number 8 which symbolizes a new beginning, actually begins each element of the phrase Fk I'm crackproof. In addition, when we begin the phrase on the first 8, it fits perfectly around the existing K and M already present in the code and thereby creating a cyclical format, where the code ends and begins with the same letter. The Little List Letter provided the solution to the Button Letter and Mount Diablo code that preceded it. His next communication, the 13 Hole Postcard, provided the solution to the 13 Symbol Cipher before that, and finally the Halloween Card provided the solution to the 340 cipher. Three chronological solves to the three previous ciphers - and the only thing we had to add was the number "5", for which he inserted the hashtag and arrow. Why look for convoluted and excessively complicated solutions to these ciphers, when the Zodiac Killer gave us all the answers literally word for word.

This isn't a case of dragging wording from the entire Zodiac collection of cards and letters, but using just the two crosshairs of the Little List Letter, followed by the 13 Hole Postcard and Halloween Card. The bold, black circle and "PS. The Mt. Diablo Code concerns Radians and # inches along the radians" to answer the Z32. The 13 holes, red cross, "paradice" and "slaves", and "sorry no cipher" to answer the Z340. And finally, "Fk, I'm crackproof" to give us a shorthanded version of his name, while still retaining his anonymity. Three answers in just three months. The alternative is that the codes are genuine, the designs on the 13 Hole Postcard and Halloween Card are devoid of any purposeful meaning, and the big-headed, braggart called Zodiac, kept his lips 'butoned' for however many years afterwards.

The Zodiac Killer gave us the answers to his six unsolved ciphers by March 13th 1971 without ambiguity, but effectively gave us all the answers by October 27th 1970. The Zodiac gave us the answer to the Mount Diablo code (32 symbol Cipher} in the Little List Letter on July 26th 1970. In fact, he gave us the answer word for word, in the form of Radians and 5 inches along the radians (all we had to do was add the number 5 where he placed the arrow and hashtag}. The 13 Hole Postcard on October 5th 1970 gave us the answer to the 13 Symbol Cipher word for word, in the form of Fk I'm crackproof. The Halloween Card on October 27th 1970 gave us the answer to the 340 Cipher word for word, in the form of Paradice and Slaves. No mathematics was required and no manipulation was needed - all we had to do was use the three phrases that Zodiac provided us with in three consecutive communications, to answer the three previously unsolved ciphers. But that wasn't all. The Zodiac gave us the answer to both the Fairfield Letter codes of December 7th and 16th of 1969, again word for word using the Halloween Card. The 18 unsolved characters in the 408 cipher he again gave us the solution word for word, using the trinity of communications on July 31st 1969 and following letter on August 4th 1969, when he revealed his pseudonym to the world. However, there is even more.

The Zodiac Killer's 408 Cipher was effectively a written message that he enciphered into characters. When you take a look at the decoded message, it isn't structured and organized - because one line or row bleeds into the following. The Zodiac Killer didn't contain his words within the confines of one row. For example, when he opened the cipher with "I like killing people", the letter E is positioned at the beginning of the second row. This randomness is not displayed in the answers to his remaining six unsolved portions of code. The answer to the 18 unsolved characters, the 340 Cipher, the two Fairfield letters, the 13 Symbol Cipher and the 32 Symbol Cipher are all organized and deliberately structured, where every single solution and word is contained within each line - and do not leak from one row to another. Let us take a look at the 13 Symbol Cipher that exhibits symmetry within its design.

When the Zodiac's solution or answer to the 13 Symbol Cipher was inserted into the code above, it showed an organized and structured pattern without a word bleeding from one end of the cipher to the other. The Zodiac Killer gave us the cyclical solution of Fk I'm crackproof on October 5th 1970, and followed this up with the line "This is the Zodiac speaking Like I have allways said, I am crack proof" on March 13th 1971. But in the Los Angeles Letter you will notice he separates "crackproof" to "crack proof", exactly how it is found in the 13 Symbol Cipher. It does not bleed from the end of the cipher to the start.

The first 8 begins FK. The second 8 begins IM. The third 8 begins CRACKPROOF. But CRACK and PROOF are separated, without either word being fragmented. The FK and IM also fit nicely around the existing K and M in the cipher. The cipher solution maintains an organized and symmetrical appearance. The introduction on the April 20th 1970 letter now read "This is the Zodiac speaking. By the way have you cracked the last cipher I sent you? My name is Fk, I'm crackproof". He was leading us into the belief these were his initials.

The Paradice and Slaves configuration from the Halloween Card to the 340 Cipher also exhibited form, with Paradice exactly bisecting the columns of the 340 Cipher, and Slaves exactly bisecting the rows of the 340 Cipher in a 17 X 17 pattern. Each word contained within a row or column. The Halloween Card envelope providing us with "sorry no cipher" in a cross formation, not only telling us that the 340 wasn't a standard cipher, but the design of the 340 was to be found in a cross formation.

The 32 Symbol Cipher also adhered to a solution where no word bled from one row to another. The 32 Symbol Cipher contained two rows of 17 and 15 characters - obviously created this way for a purpose. When we discovered that the number 5 was to be inserted into the cipher using the arrow and hashtag, the answer of Radians and 5 inches along the radians again fell perfectly into the 32 Symbol Cipher with no word extending from one line to another. You will notice that when the Zodiac Killer provided us with the answer in the July 26th 1970 Little List Letter, he self-contained the answer on a separate line, with the first Radians beginning with a capital letter. This was the beginning of the code solution.

"PS. The Mt. Diablo Code concerns Radians and # inches along the radians" was in fact Radians and 5 inches along the radians. When this is placed into the 32 Symbol Cipher, you will notice that once again it retains separation, with "inches" ending line one, and "along" beginning line two. Each word is contained within the line. This organization and structure flies in the face of the solved portion of the 408 Cipher and implies a deliberate and calculated design. But we need to take it even further.

Explained in greater detail in the article The Answer to the Z38 Code, the structure of the Zodiac 38 character cipher was pointed out. The code below has been structured with different character counts on each line (unlike the 408 and 340 ciphers), but is instead arranged in a formation of 12 characters on line one, 7 characters on line two, 5 characters on line three, 6 characters on line four and 8 characters on line five. This may suggest that the words are contained separately on each line, without running from one line to another. We would expect Slaves and Paradice to be grouped together - and the last two lines satisfy this character count of 6 and 8. We then have three lines remaining of 12, 7 and 5 characters. By Gun satisfies the 5 characters, By Knife satisfies the 7 characters, and By Fire, By Rope satisfies the 12 characters. This forms the basis of the completed 38 character code solution, mimicking the second Fairfield Letter design and the exact wording on the Halloween Card configuration. Furthermore, no word extends from one line to another, exactly as displayed in the above codes.

For anybody believing that the two Fairfield letters mailed on December 7th 1969 and December 16th 1969 were just a hoaxer, unrelated to Zodiac, then they have to explain, not only what purpose they served, but how the 38 character code manufactured by a lazy imbecile, incapable of even recreating a credible Zodiac Killer communication, just so happened to design five lines of 12, 7, 5, 6 and 8 characters, which could by sheer accident allow by fire, by rope, by knife, by gun, slaves and paradice to fall nicely onto each line. Ten words, self-contained on each line, which just happened to correlate with the October 27th 1970 Halloween card, ten months in the making. Not to mention, that by fire, by rope, by knife, by gun, slaves and paradice can be found in the "word search" 340 cipher just 29 days prior, in exactly the same design as the Halloween card.

Any doubts that the December 7th 1969 coding was a hint to the solution of the 340 cipher, should have been lessened by the inclusion of many repeating sequences of characters from the November 8th 1969 offering. The above configuration in the 340 cipher will probably be described as accidental by eminent codebreakers. However, if the December 7th 1969 author was just an ignorant charlaton, bereft of the solution to the 340 cipher, who just slapped a quick and meaningless 38 character code together, then it has to be purely by chance once again, that he managed to fortuitously create a code of 38 characters that mimicked the exact character count of by fire, by rope, by knife, by gun, slaves and paradice, present in two other cryptic communications mailed by the Zodiac Killer. Not only was this extremely lucky, but the clown impersonator of Zodiac, would for a futher time, just happen to create another cryptic addition on December 16th 1969 that mimicked the Zodiac designs in the 340 cipher and Halloween card.  

The Zodiac Killer was rather quite polite on November 8th 1969, when he cordially requested "could you print this new cipher in your frunt page?" However, after 38 days his patience was running thin, aghast at the inability of code breakers to pry open his simplistic cipher. In fact, he was starting to get bloody pissed off with authorities, demanding "you better print" in his December 16th 1969 letter (see right). Underneath his demand was yet another clue to his 340 cipher, and a design that again mimicked the yet to be mailed Halloween card.

The Tim Holt comic book connection unearthed by Tahoe27 (displayed in the Halloween card), not only contained the four phrases of by gun, by knife, by rope and by fire in each quadrant, but they were preceded by the word "death" in the comic itself. Exactly as depicted in the configuration on the right.
There are five characters, followed by four crosshairs placed around a larger crossed circle. This hoaxer was certainly having a bit of luck, creating 38 characters to mimic the Halloween card words of paradice, slaves, by gun, by knife, by rope and by fire, but also mimicking the design - including each mode of murder by the possible 5-letter introduction of "death", found on the wheel of the Tim Holt comic book.

The luck doesn't end there mind. The author of the December 7th 1969 letter wrote the words "I just need help". The phrase "please help me" would appear thrice in the authenticated Melvin Belli letter on December 20th 1969, despite the fact neither of the two Fairfield letters were ever published in the newspapers. Damn, this hoaxer is seemingly getting a lot of things correct, even thirteen days and ten months in advance.

So far (including the Tim Holt comic book unearthed by Tahoe27), every single solution or answer to the ciphers can be achieved using the exact words employed by Zodiac from three consecutive communications spanning July 26th 1970 to October 27th 1970. [1] Radians and 5 inches along the radians [2] Fk I'm crackproof [3] Paradise and Slaves, and [4] By Fire, By Gun, By Rope, By Knife, Paradice and Slaves. And none extend or bleed into another line, or from end to beginning in the 13 Symbol Cipher. That is five ciphers down with one to go. 

The Zodiac Killer claimed that his 408 Cipher contained his identity or pseudonym. What was important to the Bay Area murderer was the structure exhibited by all the above codes. The characters he used were of no particular significance, because they weren't designed to be solved without future Zodiac input. This input came towards the end of his letter writing campaign, when he supplied us all the answers in just three consecutive communications. He was effectively wrapping up business. There was no way a man with such an inflated ego and inability to resist writing to the newspapers, could keep the secret to his ciphers for upwards of five decades. The answer to the 408 Cipher was given to us in just four days, contained in the trinity of July 31st 1969 letters and the August 4th 1969 'Debut of Zodiac' Letter. He claimed his identity was in the 408 cipher - and we know his identity was "Zodiac" because he gave us his pseudonym. All we then had to do, was fit Zodiac around the declaration of who he was. 

Initially, the Zodiac Killer had intended to leave 12 characters at the base of the 408 Cipher, but his accidental omission of the word "people" when he encoded his message, inadvertently left him with 18 unsolved characters. However, this was of no consequence - it was an easy adjustment. You will notice again, that the unsolved 18 characters are split into an ungainly 1 and 17 configuration. If we are to hold true to single words not bleeding from one line to another, then the single character must stand for I or A. We know that the Zodiac Killer was an egotist, beginning the 408 Cipher with "I like killing people because it is so much fun". He also began two of the July 31st letters with "I am the killer". So it wouldn't be any great leap of faith to believe that the isolated singular character on line 23 was "I". Coupling the "Zodiac" with "I am the killer" to produce "I am the Zodiac Killer" satisfies his declaration of identity and the 18 characters at the base of the 408 Cipher. We again have used only the words written by the Zodiac Killer - and no word extends from one line to another. The third of code containing his identity was mailed to the San Francisco Chronicle, which is why he began that introduction with "This is the murderer". He was reserving "I am the Zodiac Killer" for the base of the 408 Cipher.  

We now have six unsolved portions of code answered, using only the words written by the Zodiac Killer in a total of four communications. Every single answer was organized and structured to remain within each row, line and column with no manipulation whatsoever. We can wait another 50 years for these codes to be "solved" - or believe they were all answered by October 27th 1970 from the pen of the Zodiac Killer.

This is another speculative article searching for the name of the Zodiac Killer within his communications - so caution must be applied to any conclusions that are reached in the following analysis.

After the challenge by Dr. Marsh on October 22nd 1969 requesting that the Zodiac Killer give us his real name in a cipher "however complicated", the notion of a killer hinting at his name in later communications is certainly plausible. Presented in a hidden format, the Zodiac Killer knew that it could never be used as evidence against him, unless the unearthed solution could be proven beyond doubt to be the correct one. In the article Return to Sender we explored the introduction and answer to the 13 symbol cipher of "This is the Zodiac speaking. By the way have you cracked the last cipher I sent you. My name is....Fk, I'm crackproof". The Zodiac Killer effectively giving us his name, but in the shortened format. 

Three months later, the Zodiac Killer mailed the Little List letter on July 26th 1970 paraphrasing the recital of Groucho Marx's As some day it may happen from the Gilbert & Sullivan comedic opera, The Mikado. On October 12th 1970, the San Francisco Chronicle featured this letter under the title of Gilbert and Sullivan Clue to Zodiac, stating "A quiet search for onetime Ko-Ko's has turned up none that could be Zodiac. Obvious differences in physical description and handwriting comparisons have cleared all Ko-Ko's tracked down since the arrival of the July 27 letters". But what if the Zodiac Killer wasn't choosing the character of Ko-Ko because he played him in a production or even liked the theater, but the name Ko-Ko was somehow pertinent to his identity. Bearing in mind the phrase "My name is....Fk, I'm crackproof", could the Zodiac Killer's surname begin with Ko. The phrase "FK, I'm crackproof" is actually 14 letters long, but it was fashioned into a code of only 13 characters. Could this deliberate formatting indicate his initials were FK in a name comprising of 13 letters?

Although questionable Zodiac correspondence, the December 1990 Eureka card yet again featured Groucho Marx in imagery on the front of the card, promising us his name yet again. The card read "From your secret pal, can't guess who I am yet? Well, look inside and you'll find out" - and contained within was a xerox copy of two keys. This too triggered the notion of a surname beginning with K. The Exorcist letter mailed on January 29th 1974 also featured a verse recited by Groucho Marx, but more importantly, the verse of Tit-Willow by Ko-Ko was preceded by the line "Signed, yours truley", implying the character in the verse had something to do with his name. This wasn't all.

We argued that the Zodiac Killer gave us the answers to all his "unsolved" codes in his own words, and the Celebrity Cypher mailed on September 25th 1990 to the Vallejo Times-Herald may have followed a similar pattern. The name of the sender was hidden behind 5 and 8 characters totaling 13, placed on the address side of the postcard and at the foot of the communication. A Celebrity Cypher with a likely introduction of "My name is", exactly like 13 symbol cipher mailed on April 20th 1970. If the initials of the killer were given in that instance within the phrase "Fk, I'm crackproof", then there are reasonable grounds to believe the 5 and 8 letters of the name on the Celebrity Cypher begin with an F and K also. In the Return to Sender article we hypothesized the forename as "Frank", based upon the phrase "how much money you have on my head now" in reference to the stamp on the April 20th 1970 letter - and this fits nicely into the Celebrity Cypher solution. I have speculatively placed "Ko" at the beginning of the surname regarding The Mikado references, but will venture no further. There are possibilities based on the "keys" provided by the Eureka card to suggest his surname could end in "key" or "ki" such as "Kominski", however, there are plenty of other options pertaining to the xeroxed image.

Comparisons can be drawn between the April 20th 1970 and September 25th 1990 communications with respect to a name comprising of 13 letters (split into 5 and 8 characters) - and bearing in mind the Christmas card, likely mailed close to December 25th 1990 continuing the theme of promising us his name - can a link be forged between all three regarding the identity or name of the Zodiac Killer? 

THE 340 CIPHER WAS CRACKED ON DECEMBER 3RD 2020 BY DAVE ORANCHAK, SAM BLAKE AND JARL VAN EYCKE, SO THIS EARLIER ARTICLE SHOULD BE VIEWED IN RESPECT TO RECENT DEVELOPMENTS.

The following article will coalesce several pieces of work from 2019 into one cogent story regarding a handful of communications mailed by the Zodiac Killer in 1970. For some, the following will be repetitive, for which I apologize. It will hopefully make the case that the Zodiac Killer was winding down his operations and ultimately revealing the answers to his Z340, Z32 and Z13 ciphers and codes, to which he knew were practically unsolvable without such a prompt. The Zodiac Killer was a narcissistic braggart, who boasted of his exploits and threatened all and sundry with the possibility of more murders and mayhem if his demands were not met, including the claim he had killed far more than could be accounted for. If we applied the same model to his ciphers and codes, we would have expected him to be unable to resist giving us the answers - or at the very least - some clues to break open his puzzles. The notion of a killer keeping deathly silent on the solutions to his codes for up to 50 years, runs contrary to everything we know about the Bay Area murderer during his brief but deadly reign. That is why I don't believe he did.

The story begins with the final thing he wrote on the July 26th 1970 Little List Letter, and finishes just two communications later with the October 27th 1970 Halloween Card. All the answers to his codes were contained in just three short months. The end of the Little List Letter read "PS. The Mt. Diablo Code concerns Radians and # inches along the radians". The Z32 was the easiest code to crack because the Zodiac Killer just gave us the answer above - the code concerned "Radians and inches along the radians". Why make it any more complicated than it has to be? A code of 29 unique symbols within a total of 32 characters is simply not solvable without a key - and there is insufficient wording on the 13 Hole Postcard, Halloween Card or Los Angeles Letter written in plain English to formulate any such key. The Z32 is even worse than giving us the English alphabet of 26 letters, replacing M with A, W with B and H with C and saying "now solve it". There is no transposition key present in the remaining three communications from October 5th 1970 to March 13th 1971, so if the Zodiac Killer was to be consistent in his inability to resist revealing his deeds, then the only realistic alternative is he gave us all the answers instead.

Not only did the Zodiac Killer give us the answer to the 32 character code on a separate line, he capitalized the first "Radians" to effectively tell us this was the beginning of the solution (he didn't capitalize the second "radians", so why the first). You need look no further than the Paul Stine police report to notice that the hashtag symbol is used in conjunction with a number. The Zodiac Killer by use of an arrow pointer underneath the hashtag, was telling us to replace the hashtag with a number value. The Mount Diablo map scale was 6.4 miles to the inch, so it is probably unsurprising that the "Mt Diablo code would concern inches". In this instance, I have placed the number 5 into place, giving us the answer to the code of "Radians and 5 inches along the radians" (which is 32 letters in length). The reason for 5 inches is self explanatory, because 4 or 6 inches from Mount Diablo to San Francisco would fall into the sea on the east and west side. The San Francisco element will be covered shortly. The Zodiac Killer also gave us a second set of crosshairs (shown below).

This was the first time the Zodiac Killer had ever placed an accentuated zero within his crosshairs alongside the acronym SFPD. This had to be the second clue to the location of the bomb. The hashtag and arrow signified the value of inches required, so this had to signify the radian value. By some massive stroke of luck (almost beyond belief), the bold, black accentuated circle fell over 246 degrees on a compass rose - which is 4 radians and magnetic north (17 degrees in 1970). Therefore, the target of his bomb must have been 4 radians and magnetic north, and 5 inches along the radians. 

All Zodiac's bomb threats were focused towards the San Francisco Chronicle and San Francisco Police Department, so placing this bomb location alongside the acronym SFPD should tell us that the threat was most likely focused toward a police station. By another massive stroke of luck, when we travel 4 radians and 5 inches from Mount Diablo, the target area for the bomb lies right by Ingleside Police Station. Allowing for a degree of flexibility of less than 1%, by the Zodiac Killer rounding off his radians and inches, along with the black circle diameter, no other San Francisco police station comes close. However, we need to find a location where a school bus would be traveling from north to south (with the sun to the east), that has an embankment on the right side (as displayed on the April 20th 1970 bomb diagram), with easy and covert access to that embankment, and within a few hundred feet from Ingleside Police Station. The Zodiac Killer certainly wouldn't have wanted to attract attention by parking on the road itself, but by accessing the incline from a secondary location - likely at the top of the embankment - he could achieve this task in relative anonymity. Fortunately for us, that location sits only 230 feet from Ingleside Police Station. The perfect location for the Zodiac Killer to target a school bus and thumb his nose at the San Francisco Police Department, with covert access to the top of the embankment via the car park of San Francisco City College.             

Then came the 13 Hole Postcard punched in the style of a 'Dick Tracy' code with a "red crucifix decoder". What are the chances that if we arranged the 13 holes into the shape of a cross and place it over the midsection of the 340 cipher both horizontally and vertically, it would reveal the wording "paradice" and "slaves"? Then, what are the chances that the Zodiac Killer would write "paradice" and "slaves" in his next communication in a cross formation on the card, accompanied by "sorry no cipher" in a cross formation on the inside of the Halloween Card envelope? - totaling three cross formations - but supposedly, all created for absolutely no reason whatsoever in just two communications. Isn't it more believable they were created for purpose. The Zodiac Killer could easily have written "sorry no cipher" just the once, but deliberately fashioned it this way to tell us that the 340 character cipher was not a cipher after all. It was simply a design of "paradice" and "slaves" as exhibited by the Halloween Card. Throw in a few bigrams, pivots and 'corrected sixth line', and hopefully it will look convincing. 

All these clues from the back end of the Little List Letter to the Halloween Card giving us the literal answer to both the Z340 and Z32 in "paradice" and "slaves", and "Radians and 5 inches along the radians". Could either the 13 Hole Postcard or Halloween Card give us the answer to the Z13 as well? Again, totally unsolvable because of its limited number of characters, the Zodiac Killer could either keep quiet for up to fifty years or give us the answer.

From a previous article: On January 29th 1970, the Yellow Cab Company put up a thousand dollar reward for any information leading to the arrest of the Zodiac Killer. In addition, the Teamsters Union which represents the Yellow Cab Company were reported in the San Francisco Chronicle to be considering offering a further reward on February 8th 1970 in the case of Paul Stine and Charles Jarman (another taxicab murder victim). The April 20th 1970 letter gave us the code and was immediately followed by "I am mildly cerous as to how much money you have on my head now". The October 5th 1970 postcard gave us the possible solution of "Fk, I'm crackproof" and was immediately followed by "What is the price tag now". These are the only two communications in which the Zodiac Killer asked the police the price of his capture. These two communications not only had a code and an answer that fitted the code, but both were followed by the exact same question. When the Zodiac Killer was designing his 13 Hole Postcard, it is very likely he had at his disposal a copy of his original April 20th 1970 letter, or the San Francisco Chronicle newspaper cutting below, to which he was now supplying the answer. This may have been the trigger that influenced him to repeat the phrase "how much money you have on my head now" into the very similar "What is the price tag now". The Zodiac Killer, in essence, had inadvertently bound both communications together through phraseology, as well as code and solution.   

The Zodiac Killer introduction would now give us his name (albeit his initials) in absence of his full name. It would also read fluently as a sentence, as follows: "This is the Zodiac speaking. By the way have you cracked the last cipher I sent you? My name is Fk, I'm crackproof". Nobody realistically believed he was going to supply his full name, but this way he satisfies the promise in a restricted format. Two communications mailed nearly six months apart, with a solution that satisfies the code, as well as a satisfactory introduction to the code - and both followed by the same question.    

The three 8's (representing Jesus Christ in gematria), along with the number 8 which symbolizes a new beginning, actually begins each element of the phrase Fk I'm crackproof. In addition, when we begin the phrase on the first 8, it fits perfectly around the existing K and M already present in the code and thereby creating a cyclical format, where the code ends and begins with the same letter. The Little List Letter provided the solution to the Button Letter and Mount Diablo code that preceded it. His next communication, the 13 Hole Postcard, provided the solution to the 13 Symbol Cipher before that, and finally the Halloween Card provided the solution to the 340 cipher. Three chronological solves to the three previous ciphers - and the only thing we had to add was the number "5", for which he inserted the hashtag and arrow. Why look for convoluted and excessively complicated solutions to these ciphers, when the Zodiac Killer gave us all the answers literally word for word.

This isn't a case of dragging wording from the entire Zodiac collection of cards and letters, but using just the two crosshairs of the Little List Letter, followed by the 13 Hole Postcard and Halloween Card. The bold, black circle and "PS. The Mt. Diablo Code concerns Radians and # inches along the radians" to answer the Z32. The 13 holes, red cross, "paradice" and "slaves", and "sorry no cipher" to answer the Z340. And finally, "Fk, I'm crackproof" to give us a shorthanded version of his name, while still retaining his anonymity. The alternative is that the codes are genuine, the designs on the 13 Hole Postcard and Halloween Card are devoid of any purposeful meaning, and the big-headed, braggart called Zodiac, kept his lips 'butoned' for however many years afterwards.  

FOLLOW UP ARTICLE:
THE ANSWER, ORGANIZATION AND STRUCTURE OF THE SIX UNSOLVED CODES