The Zodiac Killer mailed the Paul Stine letter to the San Francisco Chronicle on October 13th 1969 and stated "I am the murderer of the taxi driver over by Washington St + Maple St last night, to prove this here is a blood stained piece of his shirt. I am the same man who did in the people in the north bay area". Bearing in mind that the murderer had previously referenced the murders at Lake Herman Road and Blue Rock Springs Park under the umbrella of Vallejo on the car door of Bryan Hartnell's vehicle, it is clear that the switch to the north bay area was deliberately chosen to incorporate his latest attack at Lake Berryessa. The North Bay is a subregion of the San Francisco Bay Area, in California, United States. The largest city is Santa Rosa, which is the fifth-largest city in the Bay Area. It is the location of the Napa and Sonoma wine regions, and is the least populous and least urbanized part of the Bay Area. It consists of Marin, Napa, Solano and Sonoma counties. This is just the first of many times he referenced his Lake Berryessa attack on Bryan Hartnell and Cecelia Shepard, which claimed the life of the young woman. The November 8th 1969 'Drippng Pen' Card and 340 character cipher were pivotal to the Lake Berryessa attack in a number of ways.      

Up to this point, the Zodiac Killer had given us details of the two attacks in Benicia and Vallejo with "some facts which only I + the police know". and confirmed he was the murderer of Paul Stine by the addition of the blood stained shirt piece in the October 13th 1969 letter. Why should he then mail two communications in near tandem with one another, if one of them was not a belated offering? The wording on the front of the card, stating "Sorry I haven't written, but I just washed my pen" appeared chosen for purpose, because Lake Berryessa was the only attack he hadn't written about. Maybe it took the Zodiac time to search for an appropriate message and card, which fitted the bill regarding his exploits by the lake. Once he found a suitable card, he designed his 340 character cipher and mailed it alongside the Bus Bomb Letter, franked one day apart. If this were the case, then it's highly probable that the message in the 340 is relevant to Lake Berryessa as well.

The image and writing on the card outer marries up perfectly with the Zodiac message on the card inner. The Zodiac supplied us with his crosshairs, which underneath he wrote the months of his claimed attacks ("Des, July, Aug, Sept, Oct = 7"). This mirrored the message he wrote on the car door of Bryan Hartnell's vehicle, where he also added the months of his crimes, thereby generating another link to the crime. These were the only two occasions he did this. The reason for the 'Dripping Pen' Card choice, was because when he wrote on the car door with the same hand that he had stabbed the young couple, he transferred blood onto the pen - and hence the sardonic introduction of "Sorry I haven't written, but I just washed my pen" and the imagery shown.

If the Zodiac Killer apologized for not having written because his blood stained pen had been washed and gave us his attack months on the card inner - thereby replicating the design on the car door - then one could expect the "by knife" attribution to be present somewhere in the card or cipher as well. The card outer and card inner were inextricably linked by the act of Zodiac writing on the car door after the Berrryessa attack. Investigators asked the Zodiac Killer to confirm the "by knife" writing to prove he was the murderer and he duly obliged in the 340 character cipher. The Zodiac Killer placed "death by knife" in the bottom left quadrant of the 340 cipher and was confident that investigators wouldn't "get the news for a while". This turned out to be true, because the Zodiac Killer had to show us the workings of the 340 cipher nearly a year later, using By Fire, By Gun, By Rope, By Knife, Paradice, Slaves and Sorry No Cipher. 

Tahoe27 found the link between the Halloween Card and the Tim Holt comic book, where victims were placed on a Death Wheel. The four prominent execution methods featured on the cover were Death By Fire, Death By Gun, Death By Rope and Death By Knife, with the executioner spinning the wheel. Therefore, is it any great surprise that the Zodiac Killer turned up at Lake Berryessa dressed as an executioner and wrote "by knife" on the car door. This strongly suggests that the Tim Holt comic book not only played a major part in the October 27th 1970 Halloween Card, but in the Lake Berryessa attack, murder of Cecelia Shepard and the design of the 340 character cipher. The two communications mirror each other perfectly, with the Halloween Card even designed with an eye peering from behind a tree, mimicking the Lake Berryessa attack where Zodiac hid behind a tree to don his costume. For more information on the parallels between the Halloween Card and 340 cipher, please read Zodiac Admitted 340 Not a Real Cipher and The Answer to the Z38 Code.

However, we mustn't forget that the months and total provided on the 'Dripping Pen' Card only referenced the Zodiac's claimed murder victims (the Aug attribution referring to the August 3rd 1969 Snoozy/Furlong murders). This may suggest that the 340 character cipher only contained a basic message with regards to the murder of Cecelia Shepard - and why the cipher began with the word "Her". The "By Knife" phrase in the bottom left quadrant of the 340 cipher was, in effect, the Zodiac Killer supplying the answer to investigators about the writing they concealed on the car door. Nobody said Zodiac was going to make it easy and play by the rules. The "By Knife" attribution was in fact "Death By Knife" from the wheel of the Tim Holt comic book. 

If we now read the 'Dripping Pen' Card from outer to inner, and through the 340 cipher, it effectively reads "Sorry I haven't written about the Lake Berryessa attack, but I just washed my pen of the blood. Des, July, Aug, Sept, Oct = 7. Her death by knife. Zodiac".

The Halloween Card curiously contained 4-TEEN on the Lake Berryessa depiction. Only four teenagers had been murdered and claimed by Zodiac on November 8th 1969. They were David Faraday, Betty Lou Jensen, Deborah Furlong and Kathy Snoozy. Two communications forever linked.

# In medieval and ancient philosophy the Wheel of Fortune, or Rota Fortunae, is a symbol of the capricious nature of Fate. The wheel belongs to the goddess Fortuna (Greek equivalent Tyche) who spins it at random, changing the positions of those on the wheel: some suffer great misfortune, others gain windfalls. The metaphor was already a cliche in ancient times, complained about by Tacitus, but was greatly popularized for the Middle Ages by its extended treatment in the Consolation of Philosophy by Boethius from around 520. It became a common image in manuscripts of the book, and then other media, where Fortuna, often blindfolded (second skeleton), turns a large wheel of the sort used in watermills, to which kings and other powerful figures are attached. The origin of the word is from the "wheel of fortune" - the zodiac, referring to the Celestial spheres of which the 8th holds the stars, and the 9th is where the signs of the zodiac are placed. The concept was first invented in Babylon and later developed by the ancient Greeks. Wikipedia.

In the article Three Months After the Mount Diablo Code we showed how the Zodiac Killer gave us the answers to his three main unsolved ciphers in three consecutive communications spanning July 26th 1970 to October 27th 1970. Here we will do exactly the same thing regarding the December 7th 1969 Fairfield Letter (the companion to the December 16th 1969 letter). The December 7th 1969 letter showed traits of the 408 cipher, in which the author had simply dragged characters from above to provide filler for the remaining 18 unsolved characters. In the December 7th 1969 letter he had dragged groups of characters from the 340 cipher in similar fashion. 

Tahoe27 made an excellent discovery when she linked the October 27th 1970 Halloween Card to the Tim Holt comic book, showing the connection to the configuration displayed on the card in the wording By Fire, By Gun, By Rope and By Knife. However, the Zodiac Killer had likely made this connection much earlier than October 27th 1970, when he designed the December 16th 1969 Fairfield Letter (shown on the left}. In this communication he gave us a rudimentary design of the Halloween Card configuration preceded by the word "death", thereby satisfying the Tim Holt comic book of "Death By Fire, By Gun, By Rope and By Knife. Below I have shown the interconnectivity between the Halloween Card, 340 cipher and both Fairfield letters, demonstrating how the Tim Holt comic book played a part in the design of them all, with By Fire, By Gun, By Rope, By Knife, Paradice and Slaves the running theme.

The December 16th 1969 Fairfield Letter was essentially a very rudimentary precursor to the Halloween Card design of By Fire, By Gun, By Rope, By Knife, Paradice and Slaves. It was also very likely a clue to the December 7th 1969 code scribbled at the base of that letter, containing 38 characters. If this code followed the same way as all the others, in that the Zodiac Killer simply provided us with the answer to his codes in later communications, then what are the chances the solution depended on the wording in the Halloween Card, which mimicked the design of the second Fairfield Letter?

The December 16th 1969 Fairfield Letter stated "Look for more blood", then provided us with the Halloween Card style design of large crosshairs surrounded by four smaller crosshairs in each quadrant, intended to signify By Fire, By Gun, By Rope, By Knife, Paradice and Slaves. But the Zodiac Killer inexplicably chose the over inflated promise of 38 more victims from San Francisco, San Jose, Vallejo, Napa, Fairfield, Sacramento and Oakland. Curiously, the exact same number as characters on the December 7th 1969 Fairfield Letter. These victims, likely to be murdered By Fire, By Gun, By Rope and By Knife. So, was there a correlation between the two letters using these words? You will notice that the code above hasn't been structured uniformly like the 408 and 340 ciphers, but 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, satisfying the non-uniformity displayed by the 38 character code. We now have By Fire, By Gun, By Rope, By Knife, Paradice and Slaves running through four communications - that of the Halloween Card, 340 cipher and both Fairfield letters. The Zodiac Killer yet again supplying us with the answer to one of his codes in subsequent communications.          

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.  

This has been covered before, but I just wanted to expand in a little more detail without pinpointing a particular location.

How embarassing is the notion of a 50-year-old unsolved cipher, that we were given the answer to in just thirty one days? - and an answer that came straight from the horse's mouth. The 32 Symbol Cipher solution was served to us on a silver platter in the July 26th 1970 Little List Letter using the Zodiac crosshairs and six words. 

When the Button Letter was mailed on June 26th 1970, the Zodiac Killer gave us a map of San Francisco and Vicinity with his crosshairs centered over Mount Diablo, stating "the map coupled with this code will tell you where the bomb is set." If we were to find a perceived bomb, it is fairly obvious we have to travel a certain angle and distance from the top of Mount Diablo to find the location. Therefore, the 32 symbol code, if it served any purpose whatsoever, had to contain a measurement in the form of degrees and distance. The map scale was 6.4 miles to the inch - so that will be the distance the Zodiac Killer has to employ from Mount Diablo to make any sense. The degrees he used was radians, because he told us so in the July 26th 1970 Little List Letter. The Zodiac stated "P.S. The Mt. Diablo code concerns Radians + # inches along the radians". He is actually telling us that the 32 symbol code contains radians and inches in the solution.

"P.S. The Mt. Diablo code concerns (is about ) (has to do with) Radians + # inches along the radians". Any cipher expert such as David Oranchak, or quite frankly, any Joe Bloggs such as myself, will tell you that a 32 symbol code with only three repeating characters is unsolvable without a key. The Zodiac Killer was certainly no muppet - and clearly knew this when he concocted this jumble of random characters. But he gave us the key a mere 31 days later in the form of an arrow and a hashtag. He even gave us the answer of "Radians and # inches along the radians" on a separate line to distinguish the very fact. He then began the first "Radians" with a capital letter to emphasize this. We just had to key in the number. 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.

All of Zodiac's bomb threats were mailed to the San Francisco Chronicle newspaper - even detailing the murder of San Francisco police officer Brian McDonnell on February 16th 1970, who suffered devastating and sadly fatal injuries 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 constantly signed off his communications with the barbed acronym SFPD = 0 and threatened "there is more glory in killing a cop than a cid because a cop can shoot back". If that wasn't enough, the Phillips 66 Road Map was labelled San Francisco and Vicinity.  Based on a map scale of 6.4 inches to the mile, only 5 inches would land in San Francisco (4 and 6 inches would fall into the sea, other than Treasure Island). Fortunately, the Zodiac Killer gave us the angle from Mount Diablo, courtesy of his bold, black circle on the Little List crosshairs. It fell 4 radians (and magnetic north) clockwise from his arrowed pointer, around the clock face he provided. Radians are usually measured counter-clockwise, but the Zodiac Killer placed the bold circle exactly 4 radians "set to Mag.N" clockwise.

The answer was now extremely simple. All we had to do was insert a number in place of the hashtag, shown by the big flashing arrow pointing us in the right direction. The hashtag conveniently preceded "inches", so it's here we will slot in the number 5 - and bingo - we have our answer to the devilishly difficult 32 Symbol Cipher: "Radians + 5 inches along the radians" or "Radians and 5 inches along the radians".  By some quirk of fate, this phrase with the addition of the number 5, just happens to be exactly 32 characters in length. What an absolute criminal mastermind the Zodiac Killer was, creating a code that we only had to add one character to. As with all the best puzzles, the answer is usually hidden in plain sight. There is a possibility that the code reads "4 radians and 5 inches along the radian", but because the Zodiac Killer inserted one hashtag, it is more likely this is the only addition required.        

In the Little List communication it is apparent that Zodiac Killer gave us two prominent crosshairs: [1] with the accentuated black circle with SFPD=0 alongside, and [2] the extra large crosshairs with "P.S. The Mt. Diablo code concerns Radians + # inches along the radians" scrawled across it. Attaching these important additions was clearly done for purpose, thereby informing us of the radian value required, and the correlation between the crosshairs on the Phillips 66 Map and the measurements of radians and inches. The importance of a second set of crosshairs and their position, regarding the solution of the 340 cipher on November 8th 1969 could be significant in that case also.

With 29 unique characters in a 32 character code, any correlation between the characters and alphabetical solution is going to be minimal. What we do have in the solution above, is no word running from one line to the next, with the letter C beginning the word radians at the start and end of the code. As with any cipher, the Zodiac Killer had the opportunity to provide us with a key in later communications, which he effectively did for cipher 2, 3 and 4 when he gave us the answers literally word for word. What we have to consider are the three "cryptic messages" he gave us in three consecutive communications from July 26th 1970 to October 27th 1970. The Zodiac Killer was giving us the solutions to the ciphers before his campaign ended, albeit he wanted us to put in a modicum of effort. He told us on July 26th 1970 that the Mount Diablo code concerns "radians and 5 inches along the radians" verbatim. He then gave us the cryptic "Fk I'm crackproof" that fortunately slots nicely into the 13 Symbol Cipher in a cyclical nature. And finally, he gave us "paradice and slaves" in a cross formation (17X17) that mimicked the 340 cipher formation exactly (adding sorry no cipher in the identical formation on the Halloween envelope inner). How can three consecutive "cryptic messages" just happen to seamlessly fall into each cipher with no effort required?

We can place thousands of names into the 13 Symbol Cipher and then attempt to justify why this is correct by providing additional information on the subject. There have been hundreds of "solutions" to the 340 cipher, when we know only one can realistically be correct. This demonstrates the subjectivity of the 340 cipher to conform to what you had already decided upon before the decoding process began. You have the predetermined answer in your head and work towards that goal to the exclusion of all others. Our own biases will govern the answer we require. The 32 Symbol Cipher is too character variable to be decoded using standard cryptographic techniques, and therefore can literally give rise to an infinite number of possibilities, requiring only three characters to match. What better way to solve the ciphers than straight from the horse's mouth. The Zodiac Killer supplied us with 32 characters in the Little List Letter, 14 characters in the 13 Hole Postcard (that began and ended in the same letter), and 13 characters in the Halloween Card - all of which required no 'square pegs in round holes' technique to land unadulterated into every cipher. The notion of a braggart remaining tight-lipped about his ciphers, while still staggering around the streets of America some 50 years later, deserves a book all by itself.  

THE CODE SOLUTIONS BY ZODIAC

The Zodiac Killer mailed us three parts of one cipher on July 31st 1969, to the San Francisco Chronicle, San Francisco Examiner and Vallejo Times-Herald. In his communication to the Chronicle he stated "In this cipher is my idenity". Bearing in mind this is the only portion of cipher with unsolved characters, it could be argued that any identity the Zodiac was offering would be found at the signing off phase in this cipher. It didn't really matter, because only four days later he gave us his identity in the form of "This is the Zodiac Speaking". The Zodiac Killer clearly made a mistake when taking his draught message into his 408 cipher, accidentally omitting the word "people" from the final offering. If we therefore conclude his original identity to be left was actually six characters shorter, it would have reduced the 18 unsolved characters to 12. Using the first-person singular pronoun of "I", his identity at the base of the 408 cipher would read "I am the Zodiac", to become "I am the Zodiac Killer" upon realization of his mistake. The Bay Area murderer literally gave us the exact wording to his unsolved 18 characters through his introductions in the Examiner and Herald letters (both communications began with "I am the killer"). Once we knew the pseudonym or identity as Zodiac on August 4th 1969, the conversion to "I am the Zodiac Killer" was the next logical step. This would become a habit for the Zodiac Killer, who would ultimately give us the exact wording to solve his remaining three ciphers. Not only would he give us the solutions to the codes, but his practice of using 'filler' with no apparent correlation to the solution would continue.  

The Zodiac Killer was no master criminal in the style of Moriarty, but he was nobody's fool either. To make the false assumption he didn't understand ciphers or codes when creating his remaining three offerings to the San Francisco Chronicle, would be a misguided one. Even somebody with limited knowledge of coding, knows that giving us a 32 character code with 29 unique characters within its framework, is practically unsolvable without a key. You can literally fill in the blanks as you choose. Therefore, the only realistic solution to the two smaller codes can come in two forms: [1] The Zodiac Killer can give us a key to decrypt the code, or [2] He can simply give us the answer. The Zodiac Killer may well have chosen option two, and given us the entire solution to all his three unsolved codes in subsequent communications. In fact, the possibilty exists that he supplied us with all the answers in three consecutive communications from July 26th 1970 to October 27th 1970 - in the Little List Letter (07/26/70), 13 Hole Postcard (10/05/70) and Halloween Card (10/27/70). The Zodiac Killer was likely giving us all the solutions before slipping back into anonymity. The newspaper article on November 16th 1970 by Paul Avery, linking Zodiac to the Riverside murder of Cheri Jo Bates on October 30th 1966, likely drew one final breath from the Zodiac Killer through 1971, before his race was run.    

The "key" phrases for the four codes are *in this cipher is my identity", "the Mt. Diablo code concerns radians and inches",  "Fk, I'm crackproof" and "sorry no cipher". The 408 cipher we have examined, so we will now tackle the 32 symbol code.

The Little List Letter mailed on July 26th 1970, one month after the Mount Diablo code (06/26/70), told us the code "concerns radians and # inches along the radians". It was as simple as adding in two figures to complete the code (hence the hashtag symbol denoting a number). The Zodiac gave us the exact wording for the solution, detailed here in a previous article. As stated above, the 32 symbol code with 29 unique characters couldn't be solved without a key or the answer. The Mount Diablo map and crosshairs were the framework, onto which we "coupled" the code for the location of the bomb. The answer was likely "4 radians and 5 inches along the radian", thereby giving us the solution word for word. An alternative to this solution (where only the hashtag is replaced by the number 5), is "P.S. The Mt. Diablo code concerns Radians and 5 inches along the radians". The Zodiac didn't necessarily have to incorporate the number 4 because we already knew the radian value from the bold, black circle provided on the Little List Letter crosshairs.

The next solutions were given to us in the 13 Hole Postcard - that may ultimately become the most important communication of them all. By combining the "red crucifix" decoder and 13 punch-holes in true "Dick Tracy" style, the Paradice and Slaves formation would be revealed, bisecting the 340 cipher along its mid-section both horizontally and vertically. See the article 'The Dick Tracy 340 Cipher'. The Zodiac Killer would again push us in the right direction by revealing the 340 was "sorry no cipher", by way of a cross formation on the Halloween Card envelope just 22 days later. If that wasn't enough, he wrote Paradice and Slaves in the identical formation it could be found within the 340 cipher. Three clues within the space of three weeks. See the article 'Zodiac Admitted 340 Not a Real Cipher'.

The Zodiac Killer also gave us the phrase "Fk, I'm crackproof" (upside down) on the 13 Hole Postcard. Apart from an expletive, the other viable option here, is the Zodiac Killer exclaiming that he is crackproof, preceded by his initials. The reason for this line of thinking, is the Zodiac Killer's wording before the 13 Symbol Cipher on April 20th 1970. The code is designed symmetrically and looks contrived, with three circled 8's fashioned at its center. The Zodiac Killer couldn't have supplied us with his name with any expectation it would be solved, because the code was simply too short and capable of providing us with thousands of solutions. However, he could provide us a solution to the code by giving us his initials. By doing it this way, he is in a roundabout way, giving us his name and a solution to the code that satisfies the introduction that preceded it: "This is the Zodiac speaking. By the way have you cracked the last cipher I sent you. My name is Fk, I'm crackproof".

This solution not only fits into the 13 Symbol Cipher, but reads continuously if imagined in circular fashion. The Zodiac Killer gave us three 8's within a circle (the symbol of infinity, and regeneration and rebirth within Christianity), with the letters K and M positioned ideally in the code to fit "Fk, I'm crackproof" around. There are three elements to this phrase: Fk, I'm, and crackproof. When the entire phrase is slotted around the letters K and M, the number 8 begins each element of the phrase (as shown below). As a side note, "Fk, I'm crackproof" can be spelled using the letters from the 32 Symbol Cipher characters, with only the F and K reversed.      

The Zodiac Killer had effectively given us the exact wording of "I am the Zodiac Killer", "Paradice and Slaves", "Fk I'm crackproof" and "radians and inches along the radian" - all of which can be inserted untouched into all four ciphers and provide us with solutions that don't require a key. The idea of a killer who constantly responded to the newspapers at every turn, somehow resisting the temptation to ever disclose the workings of his codes and ciphers is a difficult story to sell. If we are of the belief that the 32 and 13 character codes are simply too short and too variable to be solved, then without a key the Zodiac Killer likely supplied an alternative. In the case presented above, the "key" and "answer" could be described as exactly the same thing - and It was just a case of transferring the wording from one communication to another in at least three of the examples.

John Rose used Dave Oranchak's webtoy to create features of the Halloween Card in just an 81 character block around the center of the 340 cipher. Some have stated that the variability of the characters in this area of the cipher have allowed the freedom to manufacture such a result. While that may be the case, a larger pattern of Paradice and Slaves is replicated in a 17 X 17 formation along both same midsections, effectively mirroring the John Rose presentation. The fact that both are even achievable in the same cipher, is worthy of mention. The Bay Area braggart must have been itching to throw us a few clues to his unbroken codes and ciphers - so the notion that he didn't give us any before he disappeared into the twilight - is somehow difficult to swallow.   

In the history of cryptography, a grille cipher was a technique for encrypting a plaintext by writing it onto a sheet of paper through a pierced sheet (of paper or cardboard or similar). The earliest known description is due to the polymath Girolamo Cardano in 1550. His proposal was for a rectangular stencil allowing single letters, syllables, or words to be written, then later read, through its various apertures. The written fragments of the plaintext could be further disguised by filling the gaps between the fragments with anodyne words or letters. This variant is also an example of steganography, as are many of the grille ciphers. Wikipedia.

The Zodiac Killer began his letter writing campaign on July 31st 1969, when he mailed three portions of one cipher to the San Francisco Chronicle, San Francisco Examiner and Vallejo Times-Herald. However, it wasn't until October 5th 1970 that his communications took on a different appearance entirely, in which the Bay Area murderer began claiming he was "crackproof" and stated "sorry no cipher", with four out of the next five communications (if we include the Monticello Card) employing the notion of a grille cipher. The '13 Hole' Postcard, possibly using a "red cross" decoder (akin to the Dick Tracy red decoder) , to be punctured by the 13 holes on the card and overlayed onto the 340 character cipher. This would reveal the enciphered "paradice" and "slaves" bisecting the 340 cipher both horizontally and vertically along its mid-section. The "sorry no cipher" in a cross formation on the Halloween Card envelope, also overlayed onto the "paradice" and "slaves" on the rear of the card, to again point to the 340 cipher configuration and let us know that it was unfortunately "no cipher" (Zodiac's Halloween trick or treat reveal). This was explored in the Dick Tracy 340 Cipher article. 

The 13 holes overlayed onto the 340 cipher in a cross formation, taken from the '13 Hole' Postcard would reveal the hidden arrangement in the 340 cipher (similar to the depiction on the right, although portrayed with yellow squares as opposed to white punch-holes). This was the arrangement already present on the Halloween Card in reveal mode.

The '13 Hole' Postcard has 13 punch-holes in the fabric of the card, the Halloween Card has an eye peeking through the knothole in the tree, and the mask on the skeleton has two eyeholes. Then (if I am correct) we have one hole punched in both the March 22nd 1971 Pines Card and the July 13th 1971 Monticello Card, which when overlayed on a map by the Sierra Club of Lake Tahoe and the Villa Montalvo woods in Saratoga, would both reveal the name of the victim in both instances. The point being, we have a rudimentary grille cipher being employed or insinuated in four communications spanning through October 5th 1970 and July 13th 1971. The arrangement of "paradice" and "slaves" on the Halloween Card, and the punch-holes in every other card during this period, revealing something significant hidden beneath. The name of Donna and Kathy in the two 1971 postcards, and the hidden configuration in the November 8th 1969 340 cipher, derived from both October 1970 communications.

The grille cipher, even in its most rudimentary form, was implied or used through four of Zodiac's last five communications from October 5th 1970. I am completely confident that the Monticello Card is fashioned in exactly the same manner as the Pines Card, separated by less than four months, with the single punch-hole revealing the location of Donner Memorial State Park (Donna Lass) and Oak Hill Memorial Park & Cemetery (Kathy Snoozy) by the Monticello neighborhood of San Jose. Two locations, two victims and two names, all bound by two postcards. If these overlays didn't drop over these locations accidentally, then why should the cross design on the '13 Hole' Postcard and Halloween Card mimic the 340 cipher accidentally as well.

Was the Zodiac Killer inspired by the simple Dick Tracy grille cipher, or had he invested in the book The Codebreakers - The Story of Secret Writing by David Khan, released the year before the Zodiac attacks began on December 20th 1968? It is without much doubt, that the grille cipher featured heavily in his final two communications of 1970, even though one could argue that the single holes punched into the 1971 postcards are more representative of an overlay, rather than a decryption technique - yet in every instance, a message was revealed through the punch-holes.

The Dick Tracy Magic Decoder was an integral part of American advertisements in the 1950s, encouraging children to eat their breakfast cereals while also capturing their interest in rudimentary code breaking. This was great for children, but likely a nightmare for parents, who were undoubtedly nagged into buying Post Sugar Crisp, Raisin Bran and Sugar Rice Krinkles to excess. The daily diet of codebreaking a fascination for many children growing up in mid twentieth century, post-war America. Fast forward to October 22nd 1969, when Dr DCB Marsh, president of The American Cryptogram Association, laid down a challenge to Zodiac. In the San Francisco Examiner article, Dr Marsh stated "The killer wouldn't dare, as he claimed in letters to the newspapers, to reveal his name in a cipher to established cryptogram experts. "Zodiac" had not done this, Marsh suggested, because to tell the complete truth in relation to his name, in cipher code, would lead to his capture. I invite 'Zodiac' to send The American Cryptogram Association a cipher code-however complicated." Therefore, wouldn't it be just like the Zodiac Killer to send the newspapers the most uncomplicated cipher code he could find, based on a code found in children's cereal boxes. I believe he may just have done exactly that.  

In the picture above, the writing states "This is your Red Decoder. Punch out white holes to decode answers to Red "Crimestopper" messages on the package. Green questions requires a Green Decoder from other Sugar Crisp, Post Raisin Bran, or Sugar Rice Krinkles packages".  

Where have we seen a possible "Red Decoder" and "Punched out white holes" in one of Zodiac's communications before.
The '13 Hole' Postcard was mailed by the Zodiac Killer on October 5th 1970, just shy of the one year anniversary of the 340 cipher. In the postcard the Zodiac Killer provided us with his "red crucifix decoder" and "13 punch-holes" in the fabric of the card. This was his very own Dick Tracy descoder. Seagull, a contributor to the Zodiac Killer Site forum, was on the right path when she stated "If I were to attempt to try something like this, to find a hidden message, I think I would start with using the shape of the crosshair symbol for the template. The problem would be to determine a size and whether or not to round the shape or square it off. Even if you managed to hit on the right size and shape, the message could still be coded. But my totally untrained cipher gut tells me that if the 340 can be solved it's might be something as seemingly simplistic as this". It may very well have been this simplistic, with everybody expecting the Zodiac Killer to make his second cipher much harder, after his first cipher was cracked with relative ease. The Zodiac Killer taking the shape of the "red crucifix decoder" as the template, to be coupled with the 13 punch-holes he added to the October 5th 1970 postcard  All we had to do was arrange the 13 punch-holes in the shape of a crucifix, so when it was placed over the 340 cipher, a message was revealed. The Zodiac Killer did add a second tier of messages in the 340 cipher, to which he revealed in the following Halloween Card on October 27th 1970. Nobody at the time understood the secret message in the '13 Hole' Postcard, which is why he added the second layer just 22 days later.    

The 13 punched holes in the postcard was the initial attempt by the Zodiac Killer to show us that the "crackproof" 340 cipher  was a Dick Tracy style code. Arranged on the template of the "red crucifix", a message would be revealed in the 340 cipher. If this first step was achieved successfully, then the message in the 340 cipher would be obvious. The "Dick Tracy Red Crucifix Decoder" with 13 punch-holes, if placed bisecting the 340 cipher both vertically and horizontally and arranged correctly, would reveal the wording "Paradice" and Slaves" on the 340 cipher. This is shown by the 13 white circles on the diagram below. Whether the red crucifix was intended to be reversed in sinister fashion (keeping the correct proportions relative to Paradice and Slaves on the 340), as hinted by the reversed writing on the '13 Hole' Postcard, is open to conjecture.

Unfortunately, nobody appeared to understand the simplicity of his message, so he added a second crucifix (or cross) just three weeks later, when he mailed the Halloween Card on October 27th 1970. Here, he added a second layer, by giving us the second part of the message in the 340 cipher. The Zodiac Killer placed the wording By Fire, By Gun, By Rope and By Knife around the crucifix of Paradice and Slaves, and added the message "sorry no cipher" in the form of a third crucifix (or cross) to the envelope inner. The reason being, the 340 was "no cipher" - it was a simple Dick Tracy punched hole decoder style puzzle. The Halloween Card began with "From Your Secret Pal", so it's no surprise that it contained a secret message also. If you create the 37 punched holes in the style of a Dick Tracy Decoder (shown in the above right image) and place over the 340 cipher, the By Fire, By Gun, By Rope and By Knife wording is revealed - and derived from the Halloween Card. The respective 'method of death' remaining in each quadrant of the 340 cipher (9 by 10 and sharing the central column). 

The Zodiac Killer manufactured the Halloween Card to depict thirteen eyes, often suggested as the Eye of Horus. Funerary amulets were often made in the shape of the Eye of Horus. The symbol was intended to protect the pharaoh in the "afterlife" and to ward off evil. Ancient Egyptian and Middle-Eastern sailors would frequently paint the symbol on the bows of their vessels to ensure safe sea travel. This would certainly give us Paradice, Slaves and the Afterlife in one neat package.

Osiris, is the Egyptian god of fertility, alcohol, agriculture, the "afterlife", the dead, resurrection, life, and vegetation in ancient Egyptian religion. This normally wouldn't be relevant, but for the Dick Tracy Decoder Ring (designed to conceal messages or items) and the Dick Tracy Radio Show sponsored by Quaker Oats, which featured the The Black Pearl of Osiris, given to Dick Tracy to hide in the Decoder Ring. This ring had a specific design on its face, split into four quadrants just like the Paradice and Slaves configuration on the Halloween Card. In the top left quadrant is a Zodiac-like design, bearing some similarity to the crosshairs of Zodiac, along with a moon design in the lower left quadrant. "The Dick Tracy Premium was offered in exchange for five box tops of Quaker Puffed Wheat or Rice and one wonders how many uneaten boxes were dismembered by eager kids before the offer expired". See here at the Dick Tracy Depot. 

The Dick Tracy Decoder and Dick Tracy Ring were both targeted at chidren from the 1930s onwards - and both may have had an influence on the cereal munching Zodiac in his childhood years - the rudimentary coding of which may have spawned the inspiration in his design of both the '13 Hole' Postcard and Halloween Card in the October of 1970. Many people believed the Zodiac Killer, shaken by the ease to which his first cipher was cracked, devilishly formulated a far more impenetrable cipher the second time round. Yet, it may be the case, that the inspiration for the Bay Area serial killer in his design of the 340 cipher, may have been inspired by nothing more complicated than the cereal boxes of children. 

For more on this topic: Zodiac Killer Site forum and ZodiacKiller.com discussion forum.

Unable to solve the 340 cipher and crack the message (in which I'm not alone), my only recourse is to try and prove that the 50-year-old cryptogram is unsolvable. I cannot do this on my own, so I need the Zodiac Killer to give me a hand and show me that it's not a valid cipher in his own words. The Zodiac Killer only gave us two visible 'crucifixes or crosses' (without the circle) in the cards and letters, throughout his entire correspondence with the newspapers. We can assume he did this for absolutely no reason whatsoever, or these two 'crucifixes or crosses' had a purpose. The two crosses were present in two consecutive cards - the '13 Hole' Postcard on October 5th 1970 and the Halloween Card on October 27th 1970. Both these cards also contained a hint that something was unsolvable. The '13 Hole' Postcard contained the phrase "Fk I'm crackproof", while the Zodiac Killer fashioned "sorry no cipher" in a cross formation on the envelope inner of the Halloween Card. If these statements are relevant to his ciphers, then we need to marry up the design of each card to his codes. Before we start, it must be noted that PARADICE and SLAVES in the cross formation is made up of 13 letters (the A pivotal to both words), but individually both words contain 14 letters - the total highlighted on each card. 

In the image below with respect to the '13 Hole' Postcard, you will notice that the Zodiac Killer has carefully positioned the cross beneath the number 13 - and we know Paradice and Slaves contains 13 letters in the cross formation. This is placed approximately in the center of the postcard with text either side. The 13 characters identified on the 340 cipher as Paradice and Slaves exactly mirroring this formation. Below the number 13 and cross on the postcard is the pseudonym Zodiac, accompanied by his crosshairs, almost mirroring the 340 cipher formation. The most notable feature on the 340 cipher is the corrected sixth line involving the letters F and K. Highlighted with a blue rectangle on the '13 Hole' Postcard we have "Fk I'm crackproof" written upside down. All we have to do now, is rotate the '13 Hole' Postcard 180 degrees clockwise to correct this text, so it can be read in the standard way. The corrected "Fk I'm crackproof" would now be present in the top right quadrant, just like the correctred FK in the 340 cipher.        

The Halloween Card also has the cross formation of Paradice and Slaves. This not only mirrors the "sorry no cipher" formation he provided on the envelope inner, but mirrors the 340 cipher formation also. In essence, the Zodiac Killer is telling us by extension that the 340 cryptogram is no cipher. Two consecutive communications, probably close to the anniversary he created the 340 cipher, and both designed to reveal the hidden crucifix or cross within the 340 cipher. Throw in the four By's in each quadrant and the pseudonym Zodiac from the '13 Hole' Postcard, along with "Fk I'm crackproof" and "sorry no cipher", and we have the Zodiac in his own words admitting the 340 character cryptogram has no solution. On the other hand, the Zodiac Killer is widely believed to be a liar - so maybe there's a message after all.

But just in case, let us stick "Fk I'm crackproof" into his third cipher and see if that's unsolvable as well.        

The Zodiac Killer again uses 13 characters/letters in his design, with the feature of three circled 8's. The circle and number 8 can be used to represent infinity or something of a cyclic nature. The cipher came with the handily placed K and M in the center of the code. All we have to do is place "Fk I'm crackproof" into place using these two letters (shown in blue), and in an unusual stroke of luck, the phrase is cyclic in nature. In addition, the three 8's (shown in green) just happen to begin each element of the phrase "Fk I'm crackproof" (Fk, I'm and crackproof). The Zodiac Killer may have twice told us his ciphers were unsolvable in the '13 Hole' Postcard and Halloween Card, but here he simply wouldn't shut up.

"This is the Zodiac speaking. By the way have you cracked the last cipher I sent you. My name is FK, I'm crackproof".

It has been claimed by Kathleen Johns that she received phone calls and a Halloween card (likely October 1970) from the Zodiac Killer, addressed "To the woman in the blue station wagon". This greeting card may have been simultaneously mailed with the Halloween card to Paul Avery on October 27th 1970, so it would be interesting to search for correlations between the 10/27/70 Halloween card and the abduction of Kathleen Johns. If the two Halloween cards were mailed by the Zodiac Killer around the same timeframe, then the inclusion of "by fire" alongside "To the woman in the blue station wagon" would leave little doubt that the two are connected. Traveling clockwise around the 10/27/70 Halloween card, the Zodiac Killer presented the weapons he used in the correct order of their appearance up to March 23rd 1970 - By Gun, By Rope, By Knife and By Fire. The young woman apparently forwarded this card she received to newspaper reporter Paul Avery, but like everything else in the Zodiac case it disappeared into the ether (assuming her story is true). It has been claimed that if the Zodiac was responsible for the mailing of a Halloween card to Kathleen Johns, then he was responsible for her abduction, because no mention of her driving a blue station wagon was published in the newspapers. Without trawling the entire newspaper collection from 1970, I cannot verify this detail one way or another. 

As has already been suggested, the Zodiac Killer (or her abductor) would have had ample time to rummage through her vehicle after her ordeal was over and search for any letters or documents that contained her address and telephone details. Having deposited his fingerprints all over her vehicle, this may explain why he thought it easier to torch her 1957 Chevrolet, and why he returned to her vehicle after the 2-hour abduction - to gather information for his future correspondence. 

Kathleen Johns effectively contradicted herself when she named Lawrence Kane as her likely abductor that night, because he would have been 45 years of age on March 22nd 1970. She described her abductor as white, around 30 years of age, 5'9" in height, 160 lbs, dark hair, clean-cut and having the traits of a serviceman. So how can we reconcile this difference?

For people who still believe that the Zodiac Killer was 20-30 years of age during his attacks, while also believing that the Kathleen Johns abduction was the work of the Zodiac Killer, we have to consider the amount of time she spent in his vehicle and her detailed description regarding the interior of the vehicle. Kathleen described his car as messy and had noticed men's and children's clothing scattered about, along with books and papers, a black rubber-handled flashlight, and two colored plastic scouring pads on the console dashboard. Kathleen estimated that the smaller patterned T-shirts were designed in the age range of 8-12 years. Unless the Zodiac Killer was a traveling salesman selling children's clothing, or had borrowed the vehicle, a reasonable assumption would be that these haphazardly scattered clothes were part of a family vehicle. If Kathleen Johns upper estimate of the clothing was correct at 12 years - and a 20 to 30 year Zodiac conceived this child - he would have been approximately 8 to 18 years of age at the time (12 to 22 at the lower estimate), making the case for a Zodiac Killer of at least 30 or above more believable. If you don't accept that these clothes were necessarily the clothing of the Zodiac Killer's chidren, then an alternative explanation is necessary.

In 1972, the average age of fathers of newborns in the U.S. was 27 - so if the Zodiac was the biological father of the 12-year-old who wore the clothing present in his vehicle, then the statistical average would suggest a killer of about 39 years of age in 1970, in closer proximity to the age of Lawrence Kane (who she identified as her abductor), and very close to the average age of 40 described by three sets of eyewitnesses at Presidio Heights.   

Howard Davis wrote on the old zodiackiller.com message board that "This woman felt that the PD rednecks were put off by Kathleen Johns hippy appearance and really didn't put much credence or interest in her recounting the event of that night". Was the same conclusion on the appearance of Kathleen Johns drawn by the Zodiac Killer, who paraphrased the Gilbert & Sullivan's Mikado in his communication on July 26th 1970, opening with the lines from 'As Some Day it May Happen', performed by Ko-Ko. The beginning of Act One stated "As some day it may hapen that a victom must be found. I've got a little list. I've got a little list, of society offenders who might well be underground, who would never be missed, who would never be missed".

Did the Zodiac Killer regard Kathleen Johns hippy tendencies as part of the counterculture or underground movement that he had on his "little list".- people that wouldn't be missed? The letter mailed only two days earlier to the San Francisco Chronicle would suggest so. He wrote on July 24th 1970, threatening "This is the Zodiac speaking. I am rather unhappy because you people will not wear some nice (Zodiac symbol inserted)  buttons. So now I have a little list, starting with that woeman + her baby that I gave a rather intersting ride for a coupple howers one evening a few months back that ended in my burning her car where I found them". The phrase "I now have a little list, starting with that woeman + her baby" appeared to suggest that her escape would be short-lived and that some day it might happen. It appeared that three months later she may still have been in his sights, when she apparently received a Halloween card from her abductor at her home address. He had promised to "start" with her and he wasn't finished yet.

The 'As Some Day it May Happen' verse ended with "But it really doesn't matter whom you place upon the list, for none of them be missed, none of them be missed". Sadly, Kathleen Johns is no longer with us and deeply missed by her loved ones - but fortunately for her family and friends, it wasn't at the hand of the Zodiac Killer.

There are innumerable theories on the October 27th 1970 Halloween card, including here on this site, but none have adequately explained the strange symbol on the upper left corner of the envelope or the foot of the card inner. The cattle branding was a good idea, yet it conveniently ignored the four dots present in the design. In both instances, on the envelope and card, the symbol was followed by the letter Z. This lends credence to the notion, it represents a statement followed by his signature. The Zodiac, from November 8th 1969 to March 13th 1971, was fairly consistent in giving us a running victim total, with the only two notable exceptions being the April 28th 1970 Dragon card and the July 24th 1970 Kathleen Johns letter. With respect to the Dragon card, he had given us 10 victims only eight days earlier, so clearly there was no update on the total, and with respect to Kathleen Johns, she survived the encounter so no update was necessary. The Zodiac Killer repeated the victim count of 13 on the October 5th 1970 '13 Hole' postcard because his previous letter proclaiming 13 victims had not been published in the newspapers at this juncture, The July 26th 1970 Little List letter proclaimed 13 victims, while the October 27th 1970 Halloween card issued us with the number 14, indicating that victim 14 possibly lay between these two dates.      

We know the Zodiac Killer was responsible for 5 victims - the rest he inferred by increasing his total periodically. The only victim we know of between July 26th 1970 and October 27th 1970 that was subsequently claimed by Zodiac, was Donna Ann Lass, who disappeared from the Sahara Tahoe Hotel & Casino in the early morning hours of September 6th 1970. We know he was insinuating his involvement in her disappearance because of the March 22nd 1971 Pines card mailed to Paul Avery at the San Francisco Chronicle, just like this communication. 

However, although believed murdered, the body of Donna Lass has never been found - and on October 27th 1970 she was still classified as missing. Therefore, any running victim total on this card may reflect the current status regarding Donna Lass within its design. The March 22nd 1971 Pines card teased us with the possible location of where her burial site may be found, by placing a punched hole in the top right corner. Why should this communication be any different, when we consider the design in the top left corner of the envelope and the same design placed within the card, not withstanding, that victim 14 should have fell between July 26th 1970 and October 27th 1970, which the disappearance of Donna Lass did. 

The numerous eyes spattered over the entire card should have told us we need to be looking for something - or more specifically - looking for victim number 14. I have considered the possibility of the symbols being interpreted as "Zodiac Victims Fourteen" or "Zodiac Fourteen", but this doesn't adequately explain the four dots present in the design. It also doesn't make any sense with respect to the letter Z accompanying it on either the envelope or card inner. The phrase created would read "Zodiac Victims Fourteen, Zodiac" or "Zodiac Fourteen, Zodiac". There has to be another answer, incorporating the design of the card and the 13 eyes splashed all over its face. The 13 eyes suggestive of only 13 deceased victims, looking for the 14th victim. The Zodiac Killer would eventually claim his involvement in the disappearance of Donna Lass, so the Halloween card "looking for the fourteenth victim" makes perfect sense with respect to the dates. Take a look at the card below.   

If we follow the green, yellow and blue rectangles in that order, it can be seen how this spells out "look for fourteen". If we follow the green, yellow and blue circles in that order, it can also be interpreted as "look for fourteen". The first part of the strange symbol isn't structured like the letter Z or the number 7, because the top angle is ninety degrees. However, it can be interpreted as the letter L. The four dots representing "four" or "for", with the F representing 14, as displayed on the hand of the skeleton and by the 4-TEEN above it. The phrase now reads coherently: "look for fourteen, Zodiac". In view of the fact that Donna Lass went missing on September 6th 1970, and his later Pines card communication insinuating his involvement in her disappearance, the running victim total (placed into this design) reading "look for fourteen, Zodiac" isn't so far-fetched.  

With both of these communications (Pines and Halloween) being addressed to Paul Avery, it is easy to consider a correlation between the two, even if the Zodiac Killer was behind the disappearance of Donna Lass or not. The "sought victim 12" attribution on the Pines card a whole different story.

Professor D.C.B. Marsh, in the October 22nd 1969 San Francisco Examiner newspaper article by Will Stevens, laid down a challenge to the Zodiac Killer to reveal his name. The newspaper stated "Dr Marsh told the Examiner today: "The killer wouldn't dare, as he claimed in letters to the newspapers, to reveal his name in the cipher to established cryptogram experts. He knows, to quote Edgar Allen Poe, that any cipher created by man can be solved by man. Zodiac has not told the truth in his cipher messages to the Examiner, the Chronicle and the Vallejo Times-Herald. Zodiac has not done this, because to tell the complete truth in relation to his name - in cipher code - would lead to his capture. I invite Zodiac to send The American Cryptogram Association a cipher code - however complicated - which will truly and honestly include his name". It is highly unlikely the Zodiac Killer would have been suckered into providing a genuine cipher of any length knowing that 'any cipher created by man can be solved by man'. The 13 and 32 symbol ciphers mailed in 1970 proved this very fact - both effectively crackproof without a recognizable key. However, the Zodiac could certainly have sent us a rudimentary message within the 340 cipher utilizing the wording contained within his 408 cipher.

Paradice and slaves is a well-trodden theme in the Zodiac communications, and as I have stated before, the Halloween card mailed on October 27th 1970 (almost the anniversary of the D.C.B. Marsh challenge) actually admitted that the 340 cipher was "sorry no cipher". The Zodiac Killer had never apologized previously for not sending a cipher in his 'cipherless' communications, so why start now. Even if the "sorry no cipher" writing on the envelope inner was to inform us that in about two seconds we had no cipher, then just write "sorry no cipher" once. The fact it was fashioned into a cross formation that mimicked the paradice and slaves configuration on the card inner, seemed designed to suggest that this configuration would be found in a cipher that effectively had no solution. The sheer fact that this configuration can also be found in his 340 cipher, exactly bisecting the cipher vertically and horizontally (17 by 17), one would like to believe is a convincing argument to suggest that the Zodiac Killer was finally admitting the 340 cipher wasn't a cipher at all. Additionally, it did mimic the 408 cipher with its inclusion of the paradice and slaves reference. Although this may be interesting, it understandably isn't enough to convince certain quarters of the Zodiac community who are steadfast in their belief that the 340 cipher contains a cogent but elusive message. Regardless, one couldn't help thinking that this wasn't the only time the Zodiac admitted the 340 cipher was devoid of any meaningful solution. Fortunately, the answer came in the communication prior to the Halloween card.  

If I am correct, and the paradice and slaves (13 letters) configuration was intentional in the design of the 340 cipher, then this is a significant point of interest. Two other notable features stand out in the 340 cipher. Firstly, the corrected sixth line where the Zodiac Killer blacks out a forward K and replaces it with a backward K. Secondly, the distinct possibility that he placed his pseudonym on the final line of the 340 cipher. All these three features are present in the '13 Hole' postcard.

Despite the fact that Zodiac made many spelling errors in his design of the 408 cipher and his communications as a whole, he seemed conscientious enough to correct one character in his 340 cipher, that inevitably would have made no difference in it being deciphered, had it contained a genuine solution. The fact he spoiled an otherwise neat and tidy presentation appeared designed to convince us that it was a genuine cipher. After all, why would Zodiac correct a collection of gibberish, if not to convince us it wasn't. The correction seemed contrived in order to validate the authenticity of the cipher, to which he would allude to in the '13 Hole' postcard.        

Many have speculated on why the Zodiac Killer reversed the bottom section of text on the '13 Hole' postcard. He certainly didn't do this for absolutely no reason, as he didn't create the "sorry no cipher" configuration for no reason either. The Zodiac Killer pasted the lettering "Fk I'm crackproof" on the '13 Hole' postcard in a first attempt at showing us the 340 cipher had no solution. The definition of crack-proof is something that is unable to be cracked, or in the case of a cipher, unable to be decoded. He used this word in his April 20th 1970 letter, sarcastically stating "This is the Zodiac speaking. By the way have you cracked the last cipher I sent you". He knew only too well that it hadn't been cracked, because it couldn't be cracked - and now was telling us it was crackproof by association to himself.

The Fk has been suggested as a shortened expletive or possibly a name - but what if we take it on face value, and the Fk actually means Fk and nothing more. It is like Ronseal and 'does exactly what it says on the tin'. The Zodiac Killer is essentially telling us that the corrected Fk on the 340 cipher was a ruse, because his cipher was crackproof. This is why the text on the '13 Hole' postcard is reversed, exactly the same as the reversed K on the 340 cipher. The K on the 340 cipher is not only reversed, but it is now much smaller than all the other characters on the 340 cipher, which is why the Zodiac Killer pastes "Fk I'm crackproof" rather than "FK I'm crackproof". ​ Crackproof, Fk and the reversal of text on the '13 Hole' postcard, coupled with the cross design of 13 (paradice and slaves), inevitably leads back to the 340 cipher. Either that, or he pasted "Fk I'm crackproof" upside down on the '13 Hole' postcard for no reason whatsoever.

What we effectively have, are two consecutive October 1970 communications stating ​"Fk I'm crackproof" and "sorry no cipher", both furnished with a cross design that mimics the appearance of paradice and slaves on the 340 cipher. It is my contention that the Zodiac Killer responded to the challenge of Professor D.C.B. Marsh, but he simply wasn't going to abide by the rules laid down by the cryptography expert, yet he stayed true to the paradice and slaves message in the 408 cipher, albeit in his own inimitable style. The paradice and slaves design in the 340 cipher (extending 17 rows down) still leaves the tantalizing prospect of three 'vacant' rows comprising of 51 unobstructed characters, that may harbor a second puzzle or message. With the Zodiac pseudonym almost appearing toward the end of the cipher, there may be a twist in the tail yet.       

There is a significant number of people who believe the Lake Berryessa attack on Bryan Hartnell and Cecelia Shepard was not the Zodiac Killer, rather an impostor or fraud masquerading as the Bay Area murderer. Despite the overwhelming evidence this attack was by the hand of the Zodiac Killer, the ever grandiose theories of a copycat or 'newspaper driven' conspiracy keep filling the message boards. If you believe the Lake Berryessa murderer was an impostor, then it is reasonable to assume that you also believe the October 27th 1970 'Halloween' card was the same impostor. The murderer of Cecelia Shepard wrote on the car door of Bryan Hartnell's vehicle, finishing his message with the immortal words "by knife". This phrase was withheld from the newspapers and wasn't known by the time the 'Halloween' card was mailed. Since the author of the 'Halloween' card wrote the phrase "by knife" within his communication and selected imagery of a an eye peering from behind a tree with the additional phrase "peek-a-boo you are doomed", it seems rather logical that the author is referring to Lake Berryessa and his escapade of vanishing behind a tree, before reemerging in his masked costume. Unless of course, he just guessed the phrase "by knife" withheld from the newspapers, by simultaneously discovering a Tim Holt comic book with the exact phrase around a death wheel. This impostor is rather a lucky chap.

​This impostor would then discover the workings of the unbroken 340 cipher, writing "sorry no cipher" on the envelope inner of the 'Halloween' card, despite the fact (to our knowledge) that nobody at this juncture had noticed that the paradice and slaves configuration on the card was also present on the 340 cipher, bisecting it at its center both horizontally and vertically. Not only had this impostor accidentally stumbled across the withheld "by knife" in the Tim Holt comic book, but he had also told us the puzzle contained in the 340 cipher. By writing "sorry no cipher" in the same style as paradice and slaves, he was effectively linking the two and stating that the unbroken 340 character cipher contained the configuration paradice and slaves within its design. It was therefore no cipher.

This links the apparent impostor to the Lake Berryessa attack, the 'Halloween' card and the 340 cipher. It is rather amazing that the impostor not only found the hidden "by knife" on the car door by inadvertently thumbing through his comic book collection just prior to the 'Halloween' card, but he found it around a death wheel that he could conveniently transfer and place it around the paradice and slaves configuration on the card. Even more fortunate, was the real Zodiac Killer had apparently allowed the option of paradice and slaves within the design of the 340 cipher, placing the word "by" accidentally in all four quadrants to equally mimic the 'Halloween' card. It is rather more logical to conclude that the designer of the 'Halloween' card also designed the 340 cipher - and because of "by knife", was the perpetrator of the September 27th 1969 Lake Berryessa attack. If you believe the Lake Berryessa attack was an impostor and not Zodiac, then by extension you have to believe the designer of the 340 cipher was the same impostor. 

​If the impostor created the 340 cipher, then he mailed the 'Bus Bomb' letter also. The 'Bus Bomb' communication was mailed in tandem with the 340 cipher and contained the same victim count of 7 in the passage "This is the Zodiac speaking up to the end of Oct I have killed 7 people". It also contained "Oct" in the same fashion as the writing on the 'Dripping Pen' card. Most people are in agreement that the 340 cipher/'Dripping Pen' card and 'Bus Bomb' letter were mailed by the same author. But if an impostor created the 340 cipher, he also sent the 'Bus Bomb' letter containing a piece of Paul Stine's blooded shirt from the October 11th 1969 taxicab murder. By extension therefore, the impostor must be responsible for the murder of Paul Stine and the October 13th 1969 letter. Furthermore, he must be responsible for the December 20th 1969 'Melvin Belli' letter, which also contained a swatch of Paul Stine's shirt. The bottom line being that, if you believe the Lake Berryessa attack to be an impostor, then you have to believe the Paul Stine murder wasn't Zodiac either, along with five other communications that include the October 13th 1969 mailing, the 340 cipher and 'Bus Bomb' letters, the 'Melvin Belli' letter and finally the 'Halloween' card. You cannot have one without the others. The logical conclusion is that the entirety were mailed by the Zodiac Killer, who was responsible for four attacks in the Bay Area. But no doubt, this will be far too boring a conclusion, in a case where facts seem to no longer matter anymore.

Whether the Zodiac Killer was responsible for the murder of Cheri Jo Bates (18) in Riverside on October 30th 1966 has been widely debated. The young woman was found brutally stabbed on Halloween morning by groundskeeper Cleophus Martin. The Zodiac Killer would lay claim to this murder on March 13th 1971 when he stated in the 'Los Angeles' letter "I do have to give them credit for stumbling across my riverside activity, but they are only finding the easy ones, there are a hell of a lot more down there". This made it curious that the Zodiac Killer's previous communication was the October 27th 1970 'Halloween' card and its obvious implications of a murder related to Halloween. Sandwiched between the 'Halloween' card and 'Los Angeles' communications was the November 16th 1970 Paul Avery article in the San Francisco Chronicle declaring there was 'New Evidence in the Zodiac Killings.'  This seemed rather convenient timing immediately after a card based around Halloween.

The Riverside and Zodiac connection was first proffered by Phil Sins, who Michael Morford was fortunate enough to interview in 2012. He stated "that as far as he can remember, he initially asked Avery to contact Riverside Police, and that he only got involved directly with Riverside Police Department after he made contact with Avery. He stated that he linked the two cases just by the overall similarity in the taunting letters. It also got his attention that Bates was killed on Halloween Eve and Zodiac sent a Halloween card. He told Avery to look into it, and get a writing expert as there were writing samples in Riverside. He says he has monitored the case since making the connection. He himself never had any suspects nor did he have any theories in particular". This peaked my interest regarding the design of the Halloween card, and whether the Zodiac Killer was finally incorporating Cheri Jo Bates into his running victim total (now 14), whether or not he was responsible for her murder or not. If Phil Sins drew a connection between the 'Halloween' card and Riverside, what else may he have observed?      

The pumpkin placed over the first skeleton has always been a curiosity - unless of course - the Zodiac Killer is effectively 'date stamping' this claimed fourteenth victim. He placed the number 14 on the hand of the skeleton and placed a pumpkin over the pelvic region, not only associating this victim with Halloween, but scoring the victim count of 14 onto the skeleton itself. Bearing in mind the murder of Cheri Jo Bates was four years prior, was this choice of imagery relevant?

David Faraday (17), Betty Lou Jensen (16) and Michael Mageau (19) were three teenage victims of the Zodiac Killer, despite the fact that Michael Mageau survived the attack at Blue Rock Springs. Cheri Jo Bates (18) was also a teenager. The Zodiac Killer wrote the number 14 on the hand of the first skeleton, so could easily have written this number again over the skull of the skeleton on the card inner (shown right). He could have written "fourteen", but deliberately chose to separate the "4" and "TEEN", indicating that these offerings were to be interpreted as two separate words. In the spoken word, this could mean FOUR TEEN or FOR TEEN. The Zodiac Killer placed twelve eyes onto the 'Halloween' card (one was already present at manufacture), suggesting that these held an important significance to the message the card was attempting to prompt from the reader. The simplest answer, when we consider the addition above the skeleton's head, is "look for teen". In totality, the Zodiac Killer is effectively saying "look for teen, who I have inscribed as my fourteenth victim, discovered on Halloween". The pumpkin attached to the skeleton should be the biggest clue in this regard. 

Phil Sins contacted Paul Avery regarding the taunting letters and the 'Halloween' card observation, so it is no surprise that the Paul Avery article surfaced on November 16th 1970 putting forth a possible connection between the Zodiac murders and the brutal stabbing of Cheri Jo Bates in Riverside. But was the Zodiac Killer telling the truth when he stated "I do have to give them credit for stumbling across my riverside activity", and was the 'Halloween' card the prompt, subsequently interpreted by Phil Sins? 

In the last article 'The 340 Cipher-Trick or Treat?' we attempted to show how the Zodiac Killer used two xeroxed keys in the 1990 'American Greetings' card to intimate that the 340 cipher should be inverted or flipped, in order to begin the message with 'This is the Zodiac speaking'. The 'Halloween' card intersecting "sorry no cipher" key, was also used to show how Paradice and Slaves was pivotal to the design of the 340 cipher. But another cryptic communication arrived just 22 days before the 'Halloween' card, on October 5th 1970, entitled the '13 Hole' postcard. The Zodiac Killer could easily have drawn or photographed the keys in the 'American Greetings' card, but opted to xerox or photocopy them. The same could be said of "sorry no cipher", which he could easily have written once. This led to the notion that these two deliberate choices had a meaning or message. This brings us to the '13 Hole' postcard.

Just like the 'American Greetings' card, why does the Zodiac Killer punch 13 holes through the fabric of this card in a 10:3 configuration, rather than just fill in 13 circles like his ciphers? On the address side these holes can be found on the extreme left of the card, which then obviously switch position when the card is turned over. It can also be noted that the text at the bottom left of the card is also flipped over. It read ​"There are reports city police pig cops are closeing in on me. Fk I'm crackproof. What is the price tag now?" The 'American Greetings' card, it was suggested, used two keys to infer the 340 cipher code should be flipped - the bottom row becoming the top row and vice versa - allowing one of only two prominent 'words' on the 340 to settle on the top row, to facilitate the opening message of 'This is the Zodiac speaking'. The second prominent word of 'Her' (that begins the cipher) would now be flipped to the bottom line of the 340. The '13 Hole' postcard gives us the first clue to suggest the likelihood of this being the case.

The Zodiac Killer punched 13 holes into the card with a hole punch, A keypunch is also a device for precisely punching holes into stiff paper cards at specific locations as determined by keys struck by a human operator. Or in computing, a mechanical device whose keys are pressed, individually or in combination, to punch holes in punched cards or paper tape that correspond to particular characters. Programs or wording can be encoded onto a punched card. Did the Zodiac Killer encode a message in a 10:3 configuration using these punched holes, that would not only take 'Her' to the bottom line of the 340 cipher, but use the identical wording on the envelope of the 'Halloween' card to achieve it?    

The message the Zodiac Killer may have wanted to convey, was that "sorry no cipher" hypothetically written on the address side of the '13 Hole' postcard, would not only separate the word 'Her', but it would effectively be inverted or flipped over to the other side when the postcard was turned. The flipped text containing "Fk I'm crackproof" testament to the fact we have a 'Flipped key', despite the boast of Zodiac claiming he was "crackproof" because of it  The 'Her' has now switched sides, thereby giving us our third key to the workings of the 340 cipher. The Zodiac Killer used two keys in the 'American Greetings' card to flip the 340 cipher, and a hole punch here to project the same message. He even added a red crucifix with the number 13 above, to highlight the connection to the 'big thirteen' letters of paradice and slaves on the 'Halloween' card he was soon to mail. Inversion was at the heart of these three communications, using keys in all instances - and all pointing to a 340 cipher that should be turned on its head. 

The first section of this article is a refresher, before we incorporate the rarely mentioned 'American Greetings' card, postmarked December 1990. This card, devoid of any handwriting on the card inner, was the sister communication to the Halloween card, also beginning with "From your secret pal", but contained a photocopy or xerox of two keys that have mystified as to their meaning. We will attempt to combine this communication with the Halloween card and explain its relevance to the Zodiac Killer's unsolved 340 cipher. As always, this analysis must be treated with a healthy dose of skepticism.
  
So firstly, I would like to press home the notion that the Zodiac Killer's 340 cipher was nothing more than a ruse, designed to stick two fingers up to the challenge laid down by Professor D.C.B. Marsh of the American Cryptogram Association (ACA) on October 22nd 1969, when he "invited Zodiac to send The American Cryptogram Association a cipher code - however complicated - which will truly and honestly include his name." The Zodiac Killer would eventually reveal the workings of the 340 cipher just over a year later when he mailed the rather cryptic Halloween card on October 27th 1970, revealing the trick, not treat, he had perpetrated on his challengers. The killer couldn't have been any more obvious when he actually wrote "sorry no cipher" on the envelope inner.

​In 1970, the Zodiac Killer mailed the Dragon card, the Kathleen Johns letter, the Little List letter and the '13 Hole' postcard, none of which stated the glaringly obvious, that he hadn't sent a cipher with any of them. Why would he then apologize for not sending a cipher with the Halloween card when it was patently apparent upon opening the communication? Even if he had wanted to apologize, why didn't the Zodiac Killer just write "sorry no cipher"? The fact he wrote it twice in the form of two intersecting lines suggests this design was created for a purpose. The only other intersecting text on the entire card were the words "Paradice" and "Slaves", so was the author of the Halloween card telling us that something he had created wasn't a cipher, only the intersecting words of "Paradice" and "Slaves"? If we could find "Paradice" and "Slaves" intersecting each other in any previously unsolved cipher, structured in similar fashion to "sorry no cipher", then this should be a strong argument to the meaning behind the Halloween card. We need to find "Slaves" running horizontally, preferably at the center of the 340 cipher and bisect it with the word "Paradice" (hopefully beginning with the letter "P" somewhere at the top of the cipher along the 9th column). 

Fortunately, nine characters along the top row is the letter "P". Then we must travel downwards 17 characters in order to create two lines of equal length and find the "E" of "Paradice". This will now be represented by the character "<".  We now have two lines of 17 characters, bisected by a "+" sign (the center of the crosshairs). The 'wings' of the crosshairs are represented by two dashes, situated in columns 1 and 17. These represent the two "S" letters of "Slaves". This is all very convenient. 

​There are only two identical characters (the "+" sign) in the 9th column along the first 10 rows, and we know the letter "A" is center of the bisecting "Paradice" and "Slaves" on the Halloween card. It is then a simple task of placing the "R" of "Paradice" and "LV" of "Slaves" into position, to exactly mirror the Halloween card formation. It is then not difficult to find the word "By" in all four quadrants of the 340 cipher, again mirroring the Halloween card. See here for visual. 

The second clue may have also come from the envelope, when the Zodiac Killer underlined the 'LAV' of the misspelled Paul Avery on the address side. The three letters 'LAV' bisected the center point of the 340 cipher. What are the odds of "sorry no cipher" mimicking the "Paradice" and "Slaves" formation on the Halloween card, which then mimicked the 340 cipher, along with  the three alphabetical letters 'LAV' being integral to both. 

The Zodiac Killer knew that the first anniversary of his 340 cipher being unsolved was fast approaching, and this Halloween opportunity of revealing his trick to the world, albeit wrapped in another cryptic message, was simply too much to resist.

The words "Paradice" and "Slaves" were decoded in the 408 cipher and featured prominently in the Halloween card, so what are the chances they were an integral part in the design of the 340 cipher as well? So much so, they may have formed crosshairs, bisecting the cipher at its midpoint? If none of the above was an intentional creation by Zodiac and it all fell out by accident, then he is certainly one hell of a fortunate designer. 

In the words of Thomas Horan, the 340 cipher was certainly the "Great Zodiac Killer Hoax of 1969".

When the Zodiac Killer mailed his trinity of July 31st 1969 communications he withheld his identity or pseudonym, but beginning on August 4th 1969 with his 'Debut of Zodiac' letter through to his March 13th 1971 'Los Angeles' letter, every single letter the Zodiac Killer mailed began with "This is the Zodiac Speaking" (excluding cards). So why should the 340 cipher message be any different - which was effectively a letter within a card. 

We do not know if the Zodiac Killer was responsible for the mailing of the 'American Greetings' card, but for the purpose of this argument we will assume that he was. On the left is the photocopy of the two keys that arrived with the communication. The two keys must have had some meaning to the sender - but what? It is clear that the sender could have photographed the keys, drawn two keys or even pasted two 'newspaper keys' onto the card, but made the deliberate choice of photocopying two keys for a reason. The act of the photocopying, one would like to believe, was done to convey a message.

A negative photocopy inverts the colors of the document when creating a photocopy, resulting in letters that appear white on a black background instead of black on a white background. Negative photocopies of old or faded documents sometimes produce documents which have better focus and are easier to read and study. Wikipedia. ​To invert something is to put upside down or in the opposite position, order, or arrangement. Synonyms of invert, are to turn upside down, upturn, upend, turn around, turn about, turn inside out, turn back to front, reverse, flip (over) or transpose. Therefore, was the designer of the 'American Greetings' card hinting that we should "invert the key" or "flip the key". In other words, the key to the 340 cipher is to "invert" or "flip" it on its head in order to read it. The "sorry no cipher" arrangement on the Halloween card envelope was equated with "Paradice" and "Slaves", but could have been written with the 'vertical' "sorry no cipher" running downwards. Could this imply that "Paradice" was meant to be flipped on the 340 cipher, running from bottom to top?  

If we go to David Oranchak's excellent Zodiac Killer Ciphers website and employ his 340 cipher Webtoy using the 'flip vertically' function, the 20th and 1st rows are flipped, the 19th and 2nd rows are flipped, and so forth. In essence, the bottom line now becomes the top line. The "Zodiac" he gave us on the 20th line is now in the perfect position on the top line to open up this communication or cipher with the infamous words "This is the Zodiac Speaking", just like every other letter from August 1969 to March 1971. 

The correspondence before the Halloween card was the October 5th 1970  '13 Hole' postcard. It too contained a cross and flipped text, stating "There are reports city police pig cops are closeing in on me. Fk I'm crackproof. What is the price tag now?"

Wouldn't it be nice if "Fk" meant "Flipped key" as well, and the '13 Hole' postcard was the third member of the trinity of solutions to the Zodiac Killer's unbreakable 340 cipher.