It shouldn't come as much of a surprise that the Halloween card mailed on October 27th 1970 was influenced (but not necessarily exclusively) by the extremely lengthy newspaper article released by the San Francisco Chronicle on October 12th 1970 entitled Gilbert and Sullivan Clue to Zodiac. The newspaper referenced his most recent boast of 13 victims, which began on December 20th 1968 when he "chalked up his first two victims" in "teen-agers" David Faraday and Betty Lou Jensen. This seemingly formed the basis of his communication when he chose a card with the introduction "I feel it in my bones, You ache to know my name, And so I'll clue you in", with the card inner raising the victim total to "4-TEEN" in "chalk" writing.  

The Zodiac Killer had previously claimed the San Jose murder victims, Kathie Reyne Snoozy (15) and Debra Gaye Furlong (14), in his victim total on November 8th 1969, which he was determined to remind the reader of on October 27th 1970 by incorporating 4-TEEN into his current total of 14, giving it a double meaning. The Zodiac Killer was correcting the newspaper by informing the San Francisco Chronicle that he had currently killed the 4-TEENAGERS of David Faraday, Betty Lou Jensen, Kathie Snoozy and Debra Furlong, despite having no involvement in the stabbing of the two San Jose girls on August 3rd 1969. 

The October 12th 1970 Chronicle article featured his 13-Hole postcard mailed in early October, which carried thirteen holes/circles punched into the fabric of the card, and almost certainly represented his running total of 13 victims. Therefore, the Zodiac Killer's incluson of four chalk circles or dots by the letter "F" in the symbol at the foot of the Halloween card inner, could very well be a mirror of his "4-TEEN" by the skull of the second skeleton. This dual phonetic offering combined his current victim total of 14 with the murder of the 4 teens, which is probably what he gave us at the bottom of the card.

The 4 white dots/circles could be suggestive of the 4 teenagers of Faraday, Jensen, Snoozy and Furlong, with the letter "F" representing "FOURTEEN". The Bay Area murderer was probably combining "Z" and "F" to inform police that "Zodiac" was now claiming "FOURTEEN", with the inclusion of 4 teenagers. The logical inference to "F" in the symbol at the base of the card, bearing in mind the "14" on the outer skeleton's hand and "4-TEEN" on the skull, would be "FOURTEEN". Most of his victim totals were positioned at the bottom right of each communication - and this was seemingly no different.

​Alternatively, we can argue that the symbol is a crude representation of Mount Diablo, which has no apparent supporting evidence in the rest of the Halloween card, and gets no direct mention in the San Francisco Chronicle article (other than it can be linked to the "Little List" letter which was featured in the newspaper). Additionally, we need to adequately explain what the four dots mean in relation to Mount Diablo. The contention that this symbol somehow looks like the 3,849 foot mountain in Contra Costa County should be qualified with an adequate explanation of its purpose within the card.

The 13-Hole postcard indicated the victim total using the number "13" and by punching 13 holes into the card. The Halloween card would also reference his current total on more than one accasion by using "14" and "4-TEEN", along with his claim of four murdered teenagers, which the Zodiac Killer possibly signified twice by highlighting the number "4" through the use of a hyphen and four white dots/circles. The Halloween card appeared like the Zodiac Killer was playing with the word "fourteen" throughout, and reminding us that David Faraday and Betty Lou Jensen were not the only two teenagers he had murdered. This wouldn't be the last time he would indirectly reference the two San Jose girls, when he continued their inclusion in the 148 character cipher/letter and Monticello card in May and July of 1971.  

This is a further examination of the 18 characters at the foot of the 408 cipher mailed on July 31st 1969, and the reasoning behind the apparent filler that made little sense. It is fairly clear that the Zodiac Killer made an error when converting his draft message into ciphertext form when he transitioned from the San Francisco Examiner to San Francisco Chronicle portion of the cipher, inadvertently missing out one line of 17 characters. This left him with the option of maybe dumping something unplanned into the remaining 18 characters to play a joke on the audience, which I have explored in the April 20th 1970, October 27th 1970, January 29th 1974 and December 1990 communications, found in an article entitled Four and a Half Years of "Me". 

​The word "ME" can be reasoned to be present in all the above four communications, but is also noticeable within these 18 characters, albeit not currently supported by the most convincing of arguments. So let's examine the 408 cipher in more depth, because on August 4th 1969 the Zodiac Killer informed the police to "cheer up", who would, once they solved the code "have me". This is despite his message in the 408 cipher stating that "I will not give you my name". The notion being that the identity he supplied was "ME", just like he eventually gave us in the "Exorcist" letter on January 29th 1974 when writing Me-37. The Zodiac Killer may not have been lying when he told police they would "have me" when they cracked the code. Below in green I have highlighted the characters that have seemingly been sourced by the Zodiac Killer from the columns above the final line. This final 24th row has 12 characters from the above columns, with 5 characters absent from the above columns. That is a strike rate of 70.5%. So if the final row really was just filler, why did the Zodiac Killer abandon this technique nearly 30% of the time? ​

Using the full 18 characters, let us examine the 11 characters either side of the run of 7 characters boxed in green. The first 6 characters only have a strike rate of 50% from the columns above, with the final 5 characters having a strike rate of just 40%. So its fairly obvious that the Zodiac Killer wasn't stringently harvesting characters from the above columns in these sections of the cipher. Therefore, if we discount the seven characters in a row, the remaining 11 only generate an overall strike rate of 45% from the above columns. But of these 7 consecutive characters found in the above columns, it is the grouping of 4 on row 8 that carry the most significance. The grouping of 4 characters on the eighth row spelling METH contain the object pronoun of "ME", which is visible on the final row - and an "identity" that the Zodiac Killer promised to give us in the cipher when he wrote to the San Francisco Chronicle on July 31st 1969. One could conclude that a promise to give us his identity when writing to the San Francisco Chronicle and supplying us with the third portion of the cipher, meant we would find his identity in the final 8 rows of the 408 cipher (or possibly the final line). On August 4th 1969 the Zodiac stated "By the way, are the police having a good time with the code? If not, tell them to cheer up; when they do crack it, they will have me". The final 8 rows of the cipher did contain "HAVE", "ME" and "ME".

The phrase "yours truly" has two main uses in English: as a formal sign-off in a letter and, informally and often humorously, as a substitute for "I" or "me"..When used in conversation or informal writing, "yours truly" is an idiomatic expression used to refer to oneself, the speaker or writer, usually in a self-deprecating or ironically boastful way. It functions as a first-person pronoun substitute. This is why it's important to note the use of "yours truley" and "Me" as the Zodiac Killer's chosen identity in the Exorcist letter on January 29th 1974. He effectively gave us "Me" twice. After he wrote "Signed, yours truley" in the 1974 letter he gave us a "Tit-Willow" verse from "The Mikado", whose very next line contained the phrase "My name is", which was previously followed by a 13-character code on April 20th 1970. A code which can easily be shown to give us the personal pronoun of "Me" (and the crosshairs) by employing a simple right shift of 8 positions from each circled 8.  It can be argued that he gave us two identities on April 20th 1970 by supplying us with both the "crosshairs" and "ME".

We also had the visible presence of "ME" and "me" in the Halloween card on October 27th 1970, which was teed up with the introduction of "I feel it in my bones you ache to know my name. And so I'll clue you in". The Zodiac didn't give us his name on October 27th 1970, but he did give us the personal pronoun of "Me" twice. The third portion of the 408 cipher (shown above) stated that he would not give us his name, although he did, once again, give us "ME" two more times. Throw in the autobiography of Groucho Marx entitled "Groucho and Me" with respect to the Eureka card in 1990, and it appears that the Zodiac Killer may have been playing a running joke on his audience for upwards of twenty-one years. 

After noticing the presence (or inference) of "ME" at least six times on April 20th 1970, October 27th 1970 and January 29th 1974, all with the promise or suggestion of his name or identity, this has been a retrospective analysis of the 408 cipher, looking for the most reasonable way the Zodiac Killer inserted "ME" into the final portion of the 408 cipher, mailed to the San Francisco Chronicle on July 31st 1969, and followed with a promise by the Zodiac Killer to "have me" on August 4th 1969 when the code was cracked. This analysis of the 408 cipher is far from satisfactory, but I believe our focus should be squarely on the four consecutive characters on the eighth line, which appeared like a deliberate choice by the Zodiac Killer to drop into the signature line of his three-part cipher. However, I would be surprised if there wasn't more to it.

FOUR AND A HALF YEARS OF "ME"        THE AUTOBIOGRAPHY OF GROUCHO MARX

I have considered what level of research and newspaper archive digging the Zodiac Killer undertook to prepare his communications, bearing in mind the dedication he devoted to mailings such as the "13-Hole" postcard, "Edward Adams" card and "Pines" postcard, to name but three. His use of the phrase "man is the most dangerous animal of all" in his 408 cipher on July 31st 1969 was taken from a direct quote of Merian C. Cooper, the associate producer of the 1932 movie, "The Most Dangerous Game".

​Uttered by Merian C. Cooper immediately after the release of the movie, it only appeared in a handful of 1932 newspapers, until the Zodiac Killer made it newsworthy thirty-seven years later. Other than the phrase "man is the most dangerous animal of all" used by the Zodiac Killer, the only other time I have found this quote, was from Merian C. Cooper in 1932, despite trawling through newspapers back to the distant 17th century. The following observations are likely coincidences, but they too are relevant to the life of Merian C. Cooper.

The exploits of Merian C. Cooper, an American filmmaker, actor, producer and air officer, have been widely publicized, including a 1932 book entitled "Wings Over Poland" by author Kenneth Malcolm Murray, featuring the bombing raids of the Kosciuszko Squadron under the supervision of Captain Merian C. Cooper in which Polish aviators fought to repel the Russians. The following newspaper cutting is taken from "The Lantern" newspaper in Ohio on December 14th 1932, describing the story as a "thrilling experience after thrilling experience on nearly every page of his book". The Zodiac Killer in his 408 cipher stated "I like killing people because it is so much fun - it is more fun than killing wild game in the forest because man is the most dangerous animal of all. To kill something gives me the most thrilling experience". Therefore, we have "man is the most dangerous animal of all" and "thrilling experience" connected to Merian C. Cooper in 1932 through book and movie, both present in the 408 cipher. This isn't particularly noteworthy, so let's move forward to 1942 and another Ohio newspaper publication.        

The Cleveland Plain Dealer newspaper in Ohio published an article about bombing raids during World War II on June 17th 1942, with the phrase "darck spot in the center of the circle of light" (see below). This is the exact phrase used by the Zodiac Killer on August 4th 1969 in his "Debut of Zodiac" letter. Before entering the film business, Cooper was a distinguished military officer. He was an aviator in the U.S. Army Air Service during World War I and was shot down and captured by the Germans. He later founded the Kościuszko Squadron of American volunteers who fought for Poland in the Polish-Soviet War, during which he was again shot down and taken as a prisoner of war by the Soviets. He achieved the rank of Brigadier General in the U.S. Army Air Forces during World War II. Colonel Cooper later served in China as chief of staff for General Claire Chennault of the China Air Task Force, which was the precursor of the Fourteenth Air Force..On October 25th 1942, a CATF raid consisting of 12 B-25s and 7 P-40s, led by Colonel Cooper, successfully bombed the Kowloon Docks at Hong Kong.  

​So, Merian C. Cooper led a bombing raid in 1942 during World War II, with the Zodiac Killer choosing the phrase "darck spot in the center of the circle of light" on August 4th 1969, which can be found in an Ohio newspaper article in 1942 about bombing raids during World War II. This coming after his 408 cipher on July 31st 1969 (four days earlier), in which the Zodiac Killer used the phrase "man is the most dangerous animal of all", taken from Merian C. Cooper, the associate producer of "The Most Dangerous Game" movie in 1932. With the phrase "thrilling experience" being used twice in an Ohio newspaper in 1932, describing the adventures of Merian C. Cooper during bombing raids in the Polish-Soviet War, from a book by ​Kenneth Malcolm Murray.

​Therefore, we have "man is the most dangerous animal of all", "darck spot in the center of the circle of light" and "thrilling experience" in two Zodiac Killer communications in the space of four days, all of which can be directly and indirectly linked to Merian C. Cooper through the newspapers. Did the Zodiac Killer do exactly the same thing in Riverside in 1966, when the author typed the phrase "it was about time for her to die" in the Confession letter? 

Merian C. Cooper was an accomplished U.S. Army Air Force pilot, trained in the art of bombing raids, so it wouldn't be surprising to know that we can find 1,000 foot crosshairs in the Nevada desert made by the National Aeronautics and Space Administrationas as early as the 1950s (used for aerial bombing). They are situated about 20 miles south of the Tonopah Test Range, part of the Nevada Test and Training Range (NTTR), which is one of two military training areas at the Nellis Air Force Base Complex in Nevada and used by the United States Air Force Warfare Center at Nellis Air Force Base. The NTTR land area includes a "simulated Integrated Air Defense System", several individual ranges with 1200 targets, and 4 remote communication sites. The current NTTR area and the range's former areas have been used for aerial gunnery and bombing, for nuclear tests, as a proving ground and flight test area, for aircraft control and warning, and for Blue Flag, Green Flag, and Red Flag exercises. 

These targets in the desert were used in training exercises to determine accuracy, which included the dropping of bombs onto crosshairs such as the one above. The Zodiac Killer used crosshairs in his opening communications and would place a similar target upon Mount Diablo to help locate his bomb on June 26th 1970. The only reason I have brought this up, is because of the specific wording he chose to use in his communication following the 408 cipher, when, on August 4th 1969 he described his methodology of targeting victims in the dark by using a pencil flashlight (which he called an electric gun sight in his "Bus Bomb" letter on November 9th 1969).The Zodiac Killer stated "What I did was tape a small pencel flash light to the barrel of my gun. If you notice, in the center of the beam of light if you aim it at a wall or ceiling you will see a black or darck spot in the center of the circle of light about 3 to 6 inches across. When taped to a gun barrel, the bullet will strike in the center of the black dot in the light".

The magazine "Battle Stories" in its #11 issue (July 1928) featured a story titled The Winged Dare-Devil, which referenced Merian C. Cooper (listed as Merian R. Cooper in some indexes). Merian C. Cooper, a real-life adventurer, filmmaker (co-creator of King Kong), and U.S. Air Force Brigadier General, had many famous and dangerous exploits. These real-world adventures likely inspired fictional "battle stories" in magazines of the era. 

There were a series of phone calls and one letter to various police departments from October 14th/15th 1969 to December 19th 1969 from the "Zodiac Killer". The phone call to Santa Rosa on October 14th/15th 1969 (almost certainly Zodiac) was likely delivered to the Santa Rosa Police Department, who had recently moved into the newly constructed Civic Center at 100 Santa Rosa Avenue on June 10th 1969.

​This phone call came within two days of the mailing of the Paul Stine letter on October 13th 1969, threatening to place bombs on various school buses, which resulted in an immediate response from the district's transportation director. Three weeks later, on November 5th 1969, somebody claiming to be the Zodiac Killer rang the Martinez Police Department at 30 minutes past midnight, stating "There's going to be a shooting at 1234 Bush Street", before immediately hanging up the receiver. The caller was continuing his threats on school teacher Daniel Williams, who had received several malicious and sinister phone calls over the previous two weeks, including an attempt on his life using arsenic. Two weeks after the Martinez Police Department phone call, on November 21st 1969, a "Zodiac" letter was mailed to the San Jose Police Department targeting a woman, which police took extremely seriously by instigating 24-hour protection on the "widow". Four weeks later, on December 19th 1969, a phone call to the San Jose Highway Patrol by the "Zodiac Killer" threatened "I am going to kill five of you officers and a family of five between now and Monday". This call came three days after the then unpublished Fairfield letter promising to kill numerous police officers.

​However, as far as we know, only one specific bomb threat was ever issued by the real Zodiac Killer outside of San Francisco. His November 9th 1969, April 20th 1970, April 28th 1970, June 26th 1970 and July 26th 1970 communications were all delivered to the San Francisco Chronicle.

​The Santa Rosa bomb threat on schoolchildren on October 14th/15th 1969 was featured in the San Francisco Chronicle on October 21st 1969 in an article entitled Fear Rides the Yellow Bus, which stated "A climate of fear hangs over the Napa Valley. The fear is over "Zodiac" and his terrifying boast to "wipe out a school bus. The district encompasses an area of Southern Napa County of 229 square miles. Sixty-four bright yellow buses travel the county roadways each day - often into areas where houses are a couple of miles apart. The vehicles go a total of 4,000 miles daily in and from elementary schools, three junior highs and one senior high school. Even before starting on its routes each vehicle has undergone a thorough check to make sure a bomb isn't aboard. Someone hinting he might be Zodiac has telephoned such a threat in Santa Rosa. The man responsible for the safety of the students who ride the buses is Fred Sowash, the district's transportation director. Since last Wednesday, when he learned of Zodiac's threat, Sowash has been devoting 18 to 20 hours a day to blunt it"

When the Zodiac Killer aimed his threat at Santa Rosa in October 1969, this was the only confirmed bomb threat outside of San Francisco by the murderer of five. But is this actually true, when we consider that seven months later, on Friday, May 8th 1970, somebody issued two false bomb threats to the recently opened K-Mart department store at 3771 Cleveland Avenue in Santa Rosa? These malicious phone calls came 10 days after the Zodiac Killer's "Dragon" card arrived at the San Francisco Chronicle and stated "I hope you enjoy yourselves when I have my blast".

​If this was a hoaxer phoning the Santa Rosa K-Mart on May 8th 1970, then they chose the only city beyond San Francisco that the Zodiac Killer had previously threatened by bomb, seven months earlier. If the Zodiac Killer had called the Santa Rosa Police Department at 100 Santa Rosa Avenue on October 14th/15th 1969, then this hoaxer on May 8th 1970. would have issued these following threats just 3 miles north of the police department, alongside Highway 101, linking San Francisco. The Santa Rosa Police Department was 500 meters east of Highway 101, while the K-Mart on Cleveland Avenue was only 120 meters west of Highway 101. 

The question we have to ask is, did a hoaxer pretending to be the Zodiac Killer choose Santa Rosa again by sheer fortune, did they select this city by virtue of one newspaper article in the San Francisco Chronicle seven months earlier, or was it the real Zodiac Killer targeting this location once again, who may have shot at a school bus in Santa Rosa on October 17th 1969?

Regardless of the threats to target schoolchildren with bullets and bombs, investigators were skeptical of the female bus driver's claim as they could find no evidence of any bullets striking the bus. One would have thought that a Santa Rosa telephone threat from the Zodiac Killer directed at school buses, followed by a woman driving a school bus in Santa Rosa reporting what she described as "a loud shot", would have stimulated less skepticism  Especially when you consider that the female bus driver in Santa Rosa reported this story before any knowledge of the Santa Rosa bus bomb threat had been published in the newspapers. It seemed that Fred Sowash took it seriously when he learned of the threat on October 14th or 15th 1969, because he devoted 18 to 20 hours a day to minimize the possibilty of an attack. However, despite his commitment, it appeared that no police vehicles were trailing this woman's school bus on October 17th 1969 as it approached Yulupa Elementary School in Santa Rosa, amidst the Zodiac Killer's threats to shoot out the front tires of a school bus and "pick off the kiddies as they come bouncing out" on October 13th 1969 , and the direct threat to Santa Rosa less than 48 hours later.

If you want to read an introductory article to better understand the following presentation, please click here. ​

When the Zodiac Killer mailed the "Little List" letter on July 26th 1970 he pretty much gave us the full solution to the Z32 by writing "P.S. The Mt. Diablo code concerns Radians + # inches along the radians". The solution contained "radians" and "inches", and all we had to do was precede each with a number, giving us the answer of "four radians and five inches". The location of his claimed bomb was never going to land on a round number, so the solution was just an estimate, giving us the complete answer of "estimate: four radians and five inches" (supplied by Andrew Gray). That is really all there is to it. 

In the "Button" letter mailed on June 26th 1970 the Zodiac Killer wrote "the map coupled with the code will tell you where the bomb is set". We have the code answer of "four radians and five inches", but we needed to couple it with the map "set to magnetic north" of 17 degrees in 1970. That is 4 X 57.3 degrees (one radian) + 17 degrees = 246.2 degrees. Therefore, the bomb was claimed to be set at 246.2 degrees from Mount Diablo (which was an estimate). The actual target was Ingleside Police Department by the Southern Freeway, which was positioned at 251 degrees  The margin of error over a 360 degree circle was just 1.3%. That is pretty damn accurate. The crosshairs with the bold, black circle on the "Little List" letter was set to 246.2 degrees and had SFPD aligned next to it, so it's clear that the target was a police station. 

The repeating ciphertext characters are now satisfied, but do we really believe that the extremely clever Zodiac Killer added the remaining 26 ciphertext characters by using random letters and symbols that meant absolutely nothing? The solution thus far gave us 246.2 degrees (which was an estimate), but what was the real value in degrees to pinpoint the exact target? What can we possibly do with 32 characters, of which 29 are unique? If you are approaching this based on techniques employed in the 340 and 408 ciphers, then the answer is absolutely nothing. Therefore, it's fairly obvious that the Zodiac Killer used a different approach. A simplistic approach as old as time. However, the only clues we had was "P.S. The Mt. Diablo code concerns Radians + # inches along the radians" and "the map coupled with the code will tell you where the bomb is set". We have already explained both of these messages from the Zodiac Killer, so one of them must have a double meaning with respect to finding the exact location the Zodiac Killer was claiming for his bomb.

If we look at the message in blue, we already have the "map" element of "17 degrees magnetic north" (as mentioned above), so did the Zodiac "couple" this with something other than four radians in the "code", to give us the remaining degrees and pinpoint the exact location of the proposed bomb. The only way to attempt this, is by attributing number values to the alphabetical letters (correctly aligned), of which there are 20 in the code. For example A=1, B=2, C=3, etc. What are the chances that these alphabetical letters would add up to 234 in the "code", to be "coupled" with 17 degrees from the "map", and give us 251 degrees to identify the exact location of the Ingleside Police Department (SFPD) from Mount Diablo? They did.

We have "four radians" in the code (229. 2 degrees) coupled with the map of 17 degrees magnetic north = 246.2 (estimate).
We also have 234 degrees in the code, coupled with the map of 17 degrees magnetic north = 251 (the exact target location).
​The idea that the Zodiac Killer gave us 29 different characters in the Z32 with seemingly no hope of a solution, should be flipped on its head. In other words, the fact that he deliberately engineered such an impossible code with no chance of a resolution, meant that there probably was one. I expect that he thoroughly enjoyed the notion of a "crackproof" code, when in fact, the solution was anything but.  If you look too deep into a problem, you will often overlook the shallow. 
​
ADDITIONAL READING: THE ANSWER TO THE MOUNT DIABLO CODE 

Recently I released an article entitled Four and a Half Years of Me, showing that there are only four communications from July 31st 1969 to January 29th 1974 where the Zodiac Killer teased us with his identity or name. In each of these communications, including the 408 cipher on July 31st 1969, 13-Symbol cipher on April 20th 1970, Halloween card on October 27th 1970 and Exorcist letter on January 29th 1974, the Zodiac Killer may have revealed his identity of "ME" numerous times. The joke was probably on us as we attempted with ever increased fervour to find a meaningful solution to his identity. The Exorcist letter itself appeared to push the boat out even further, supplying us with "Signed, yours truley" which means "ME", gave us a "Tit-Willow" verse whose next line contained "my name is", before finally giving us the visible signature of "Me-37" in his boasting victim total..

​I thought this was the final clue to the Zodiac Killer's identity but I may have been wrong, because the December 1990 "Eureka" card delivered probably the biggest joke to date, by featuring one of the greatest comedians of all time.

This festive greeting card was designed by George Schill, a contract artist with the American Greetings Card Company, who featured the imagery of Groucho Marx on the face of the snowman, with the accompanying text that promised to reveal his identity. The outer portion of the card read "From your secret pal. Can't guess who I am yet. Well, look inside and you'll find out". Once opened the card inner failed to deliver by giving us the taunting message of "That I'm gonna keep you guessin". Happy Holidays anyway". In 1990, the Zodiac Killer had chosen a card with Groucho Marx imagery on the outside and the promise of his identity on the inside, the very year that Groucho Marx was celebrated in the newspapers in October, commemorating the 100th anniversary of his birth on October 2nd 1890. 

This centenary saw several related events and releases, including a new radio series, stage revues, and articles. A play titled Groucho Marx a Life in Revue was performed at the Geva Theatre in Rochester, New York in February 1990. But if this card was chosen specifically to highlight Groucho Marx on the cover and "ME" on the inside, how could we possibly find the clue, assuming we had already made the connections in the other four communications? Look no further than his first edition 1959 autobiography entitled Groucho and Me, published the year before he performed in the "Bell Telephone Hour" in 1960, in which he played Ko-Ko, the Lord High Executioner in The Mikado. He sang Tit-Willow that featured in the Exorcist letter. The book was reissued in 1990 to mark the centenary of Groucho Marx's birth.
​
Groucho and Me is the highly acclaimed autobiography of the legendary comedian Groucho Marx, first published in 1959. Written in his own unique, witty, and irreverent style, it offers anecdotes and insights into his life and the saga of the Marx Brothers. This is Groucho Marx's main autobiography, in which Groucho tells the story of the Marx Brothers' rise, the crooked world of small-time vaudeville, and their adventures in the film industry with a "rags-to-riches story with a difference" The book was first published in 1959 by Bernard Geis Associates.

​So, did the Zodiac Killer allude to the newly publicized and reissued 1959 autobiography of Julius Henry "Groucho Marx" in 1990, effectively supplying us with "Groucho and Me" on the 100th anniversary of his birth, which the Bay Area murderer possibly commemorated by mailing the biggest joke of all and asking us to guess his identity rather than supplying the word "ME" in more obvious form? The Zodiac Killer mailed two mysterious "Secret Pal" cards to the San Francisco Chronicle (including the Halloween card on October 27th 1970) - and both offerings may have pointed us to "ME" on at least three occasions. Secret pal cards are used for various occasions, including birthdays, holidays (like Christmas), or just as a "thinking of you" gesture. The primary purpose is to send messages or gifts without the recipient immediately knowing the sender's identity.
​
This, and the above linked article, highlight the argued presence of "ME" in five communications from July 31st 1969 to Christmas 1990, all of which teased us with his identity. The theatrical Zodiac Killer may have finally brought the curtain down on his audience and taken one last bow, by using the comedic genius of Groucho Marx to play his biggest prank of all. Then he left the stage for good.

Mailed from Santa Clara or San Mateo County on December 27th 1974, the "Mary Pilker Christmas Card" became the second obvious communication about Donna Lass that has been connected to the Zodiac Killer case (she was the sister of Donna). The "Pines" postcard on March 22nd 1971 was clearly mailed by the Zodiac Killer, but what can be reasonably concluded about this festive offering 3 1/2 years later? A comprehensive argument has been put forward to reason that the Zodiac Killer was responsible for the deposition of Donna Lass' remains by Chubb Lake, near Yuba Gap and Camp Spaulding in Placer County, despite not being conclusive.

​If the Zodiac Killer was not the murderer of Donna Lass in 1970, then it would seem rather fortuitous that he used phrases like "pass Lake Tahoe areas", "around in the snow", "Sierra Club" and "Peek through the Pines", pasted onto an advertisement of Incline Village and directing us westwards, if he didn't know the burial site of Donna Lass. Not withstanding the fact that measurements between the Clair Tappaan Lodge "Sierra Club" and the punchhole in the postcard pinpointed the exact location her skull and jawbone were found in 1985/1986. This location in September 1970 was covered in several feet of snow amidst the pine trees, and was only accessible by vehicle from Highway 20 via Chubb Lake Road, Forty-Niner Way and Gonelson Canyon Road. Access to this area from Highway 20 looked extremely similar to the imagery present on the "Mary Pilker Christmas Card". Below I have added a little snow to the entrance of Chubb Lake and placed it alongside the Mary Pilker greeting card for comparison. We had to "peek through the pines" to discover the burial location.

The body of Donna Lass could have been disposed of in many ways by her killer, but both of these cards on March 22nd 1971 and December 27th 1974 featured snow and pine trees, which is exactly where her skull and jawbone were ultimately found "in 2 inches of snow" surrounded by pines. A killer such as Zodiac, who emphasized the afterlife in numerous communications throughout his campaign of terror, appeared to be suggesting that the spirit of (Saint) Donna Lass was now acting as a "Guardan of the Pines" - and by extension - was buried "around in the snow" close to somewhere resembling the imagery in the Mary Pilker greeting card.

I have scoured the internet for further clues to this mystery but have come up empty-handed, other than one reference to a Saint Domna of Nicomedia, who was a priestess of idols in the imperial palace in Nicomedia. She converted to Christianity after reading the Epistles of Saint Paul and was baptized by Bishop Cyril along with her servant. When Emperor Maximian discovered her true identity, he ordered her arrest and execution. The precise circumstances vary in different accounts, but she was ultimately martyred, often associated with the persecution that led to the martyrdom of 20,000 Christians on Christmas Day in Nicomedia. Despite the spelling of her name being slightly different, it must be noted that she was executed by beheading, with her life being commemorated every year on December 28th, the day the author of the Mary Pilker greeting card might have expected his December 27th 1974 offering to arrive at Sioux Falls in South Dakota by air mail. Although disturbing to contemplate, we know that the only remains of Donna Lass to be found was her head (skull and jawbone), so we don't know for certain if the entirety of her remains were transported to the area of Chubb Lake in Placer County.

If the roadway entrance to Chubb Lake was impassable due to the fall of snow in September 1970 (and assuming the remains were found in 1985/1986 where the killer deposited them), it would be almost impossible for the responsible to carry a body from Highway 20 to the location just east of Chubb Lake, which is described as "a mile northeast of Interstate 80" in the newspaper cutting above. The killer would have had to carry (or drag) Donna Lass 500 meters across mountainous and snowy terrain from the nearest access point on Highway 20..However, carrying just a head would be relatively easy. I don't want to belabor this grisly thought, but the Zodiac Killer didn't need to direct law enforcement to the entirety of her remains to prove he was responsible for her murder. The transport of an "offering" such as this from an area close to the Sahara Tahoe Hotel to Chubb Lake (about 70 miles) would have carried far less risk. 

If the Zodiac Killer was responsible for the Mary Pilker greeting card, was it a deliberate choice to send this communication at Christmas time, when he was able to deliver a veiled and sinister communication inferring the burial location of Donna Lass that would incorporate a festive scene to include "pines" and "snow"? Or was the date of December 28th an overriding factor in the author's decision to mail this greeting card just after Christmas day?​

​ANALYZING THE PINES POSTCARD WITH RESPECT TO THE LOCATION OF DONNA'S REMAINS
​​​PLOTTING THE DISTANCE OF THE DEAD ZONE
ZODIAC KILLER THREATS TO INCLINE VILLAGE IN NOVEMBER 1969

To determine the specific digit (finger) a print came from, no set minimum amount of the fingerprint is universally required; rather, examiners need a sufficient quantity and quality of unique features, known as minutiae, to make a reliable determination. These fine details or minutiae include ridge endings, bifurcations (where a ridge splits), short ridges, and enclosures. The location and relationship of these points help determine the digit. There are as many as 150 ridge characteristics (points) in the average fingerprint.

​However, there is no universally set minimum number to qualify as a match, and it is up to the examiner to make the decision.​ The term used in forensic science when comparing fingerprints to determine a match is identification, dactyloscopy, or ridgeology. The process involves looking for "points of similarity" or "points of identification" in the unique ridge details, formally known as minutiae. In fingerprint comparison, similarity refers to the level of agreement in features between two impressions, while dissimilarity refers to observable differences. The core process, known as friction ridge identification, involves assessing and comparing these features to determine if the prints originated from the same source. 

In other words, for William J. Hamlet to declare a "similarity" in the fingerprints retrieved from the "Little List" letter and the outside front passenger door handle of Paul Stine's taxicab, he had to observe "sufficient quantity AND quality of unique features, known as minutiae", not "sufficient quantity OR quality of unique features, known as minutiae​". What is important here, is that William J. Hamlet wasn't comparing fingerprints from two random crime scenes to determine if one perpetrator was responsible for both, he was announcing a "similarity" between two "crime scenes" we know for certain that the Zodiac Killer was responsible for. We absolutely know that the Zodiac Killer touched the outside front passenger door handle of the taxicab where a bloody fingerprint was found, and we know he touched the pages of the writing pad he used when writing and mailing the "Little List" letter.

​If the left ring fingerprint from the "Little List" letter was observed on any of the inner pages (2, 3, 4 and 5), who else would have deposited this fingerprint other than the Zodiac Killer, who presumably wrote this communication using five consecutive pages of a machine-produced writing pad, which should realistically be fingerprint free on its inner pages? Especially when we know that elimination prints were taken from San Francisco Chronicle employees and law enforcement. In fact, once San Francisco Chronicle staff realised it was a potential Zodiac Killer letter after reading "This is the Zodiac speaking" on page one, they should have proceeded no further. Law enforcement, at this point in time (July 27th 1970 when the letter was received), almost certainly would have had the common sense not to touch any part of a possible Zodiac communication with ungloved hands.

Imagine that the "Little List" letter and taxicab fingerprints exhibited overall "similarity" and only had five recognisable corresponding minutiae points such as the ones shown above (one of which was determined to be from the left ring finger). For example, one from the taxicab door handle of the murdered Paul Stine, and one from page 4 of the "Little List" letter. This number wouldn't be regarded as conclusive for a certain match, but when we factor in that both of the fingerprints were lifted from surfaces that we know were handled by the Zodiac Killer, how does this affect our evaluation? If William J. Hamlet had pointed out five minutiae points that corresponded between the fingerprints lifted from the "Little List" letter and taxicab door handle, it may not identify the Zodiac Killer, but it could certainly rule "suspects" out.

If none of Arthur Leigh Allen's 10 digit impressions (or any other individual investigated) had any of these five corresponding minutiae on any of their fingers relative to one another, from two surfaces we know the Zodiac Killer touched (one with blood from the victim), then what are the chances that Arthur Leigh Allen murdered Paul Stine, or any of the other four victims for that matter? The answer is practically zero. Particularly when we have additional bloody fingerprints on the left side dividing panel (B-pillar) of the taxicab, that correspond to the eyewitness testimony of the Robbins children who placed Zodiac at the driver side door that night. A body part of the taxicab where responding personnel had no reason to touch..

The key thing to remember here, is that it's not just about a "similarity" noted between two fingerprints plucked from anywhere - it's about a "similarity" between two fingerprints being lifted from two surfaces that the Zodiac Killer had every reason to touch. If our killer lived within a mile radius of the Springs & Tuolumne payphone in July 1969 in a permanent residence -  and the basic characteristics of the murderer had been used to narrow the search - it shouldn't have been too difficult to check the fingerprints of the limited pool of individuals, to either implicate or eliminate the said person to the murders in the Bay Area.

The FBI file made one key statement, noting that "It is not possible to determine which finger made most of the previously reported latent fingerprints in this case". In an unscientific analysis of taking the word "most" as a minimum of 60%, would suggest that approximately 40% of previously reported latent fingerprints in the Zodiac case were able to be matched to a specific finger or digit. This would mean 40% of 39, which is as little as 15 to 16 latent fingerprints that could be allocated a specific digit on the left or right hand. If the word "most" was as high as 70% or 80%, the known digits of latents would drop to 12 and 8 respectively. A figure that would probably fall further if we did not include envelopes in our analysis. This clearly demonstrates the lack of quality fingerprints previously reported in the Zodiac case, by virtue of detail and/or size of each partial fingerprint impression recovered.

In 2024 Jarett Kobek mailed me a newspaper article from the Martinez News-Gazette from February 15th 1980, in which the chief criminalist at the Contra Costa Sheriff's Development in Martinez, Gerald Mitosinka, stated "We still have the fingerprints of Zodiac Killer. We still check them against new prints found at crime sites. One examiner knows each of the Zodiac's prints by heart". Obviously, this would suggest (if true) that they should have identified the ten fingerprint digits of the Zodiac Killer from only the pages of the letters he mailed, not the envelopes and postcards, where acquiring all elimination prints is not practically feasible or reliable.​

The machine produced pages of a writing pad (preferably the inner pages of a multi-page letter mailed by the Zodiac Killer), in theory, should contain his fingerprints, if law enforcement have correctly eliminated newspaper staff and themselves as the contributor of any found fingerprints. If we interpret the FBI file when it stated "most", that it was not possible to determine 70% of the time which finger made the previously reported latent fingerprints in this case, it would mean that 30% of the time it was possible. But that would only give us 12 fingerprints in which the digit could be established. And it's highly unlikely that 12 found fingerprints would provide us with the 10 separate digits of Zodiac.

​Realistically, after eliminating newspaper staff and investigators, one might expect the remaining unidentified fingerprints on the pages of any letter to be from the Zodiac Killer. So how do we square this circle? I think we have to take the above statement of Gerald Mitosinka with a proverbial pinch of salt, because even after elimination prints, we still can't say definitively that the remaining unidentified fingerprints were donated by the Zodiac Killer. They may very well belong to the Bay Area murderer, but stating it as fact does not appear to be supported by the evidence. An assumption would have to be made after elimination. 

​To determine the specific digit (e.g., index finger, thumb) a partial print came from, there is no universally agreed-upon minimum percentage or number of minutiae points. The ability to make this determination depends on the quality and unique features present in the visible portion of the print. If we have 12 of these prints (digit recognised) that remain unidentified on the communications (inc. envelopes), it could be argued we have less than 12 reasonable fingerprints of the Zodiac Killer. Only the fingerprints found on the pages inside the envelope, not identified through elimination prints, can effectively stay in the game. Dion Walker in his YouTube video entitled "Zodiac killer FBI files serial 232 ~The ALSA3 latent fingerprint sheets" has concluded "based on the information we have, there could be no less than 11, possibly 12 latent prints on file in the FBI Zodiac file that belong to the perpetrator". 

This is a probative analysis and may be subject to change. 

You can tell if a fingerprint is from a left or right hand by analyzing specific patterns like the whorl axis slant, which shows a statistically significant tendency to slant one way or the other depending on the hand. Other methods involve analyzing multiple parameters within the fingerprint's ridges, such as the slope of the ridges, the positions of the core and deltas, and ridge counting. For loops, the direction of the flow can also be a key indicator: ulnar loops, which flow toward the pinky finger, are more common on the right hand, while radial loops (flowing toward the thumb) are more common on the left. ​

A Zodiac Killer without gloves (and minus effective airplane fingertip guards, or none at all) would inevitably have deposited fingerprints on the outside front right passenger door handle when entering the front of the taxicab. When the Zodiac Killer was seen leaving this door by the Robbins teenagers, they described a suspect who then "exited the cab by the passenger side front door, also wiping with a white rag, possibly a handkerchief. The suspect then walked around the cab to the driver's side and proceeded to wipe the exterior of the left door area". The white rag was most probably the cut section of Paul Stine's shirt. But how does a right-handed killer, who might be expected to use this hand when wiping down the taxicab, manage to leave a left ring fingerprint on the outside front passenger door handle? There are multiple possibilities.

If the Zodiac Killer had used scissors or a knife to cut the shirt of Paul Stine, he would have used his right hand, leaving his left hand free to secure the freed shirt piece. If he had immediately left the taxicab after performing this task, his left hand would have still been in possession of the shirt piece, which he could have then used to quickly wipe the door handle as he exited. Alternatively, he may have put the scissors/knife away while inside the taxicab and subsequently grabbed Paul Stine's wallet and Yellow Cab keys using his right hand, while still clutching the shirt piece with his left. As he departed the front passenger side of the taxicab he may have then pocketed the wallet and keys, obviously keeping the shirt piece in his left hand to wipe down the door handle. This would explain why a right-handed individual attempted to remove fingerprints with his left hand. So how was the bloody left ring fingerprint of Zodiac inadvertently deposited on the door handle?

The above image shows the door handle of a Ford Galaxie 500 taxicab. If the Zodiac Killer was clutching a portion of the shirt piece with his little finger and thumb, and wiping up and down and/or horizontally across the inside of the door handle with the three longest fingers (digits 7, 8 and 9) by positioning his hand at either the top or bottom of the door handle, it is easy to see how the side (or front) of his left index or left ring finger could accidentally make contact with the inner edges of the door handle. That is why it would be important to know the exact location and orientation the bloody left ring fingerprint was positioned on the door handle. 

Elimination prints were taken of responding personnel who attended the Presidio Heights crime scene, as they were of San Francisco Chronicle staff and members of the police department who touched the "Little List" letter mailed on .July 26th 1970. Therefore, the bloody fingerprint found on the taxicab and the latent left ring fingerprint retrieved from the "Little List" letter exhibiting similarities to one another, have a strong possibility of originating from the hand of our killer. Any fingerprints found on the inner pages of the five-page "Little List" letter (protected by the front of page 1 and the rear of page 5), one might expect to be the fingerprints of the author, had the San Francisco Chronicle staff ceased further examination once they read the introduction of "This is the Zodiac speaking". This, of course, assumes that the Zodiac Killer folded pages 1 to 5 in order. There should be very little to no reason why a machine produced writing pad should contain any fingerprints on its inner pages, other than that of the Zodiac Killer. Especially when using five consecutive pages over a constrained time period to author this letter.

It is clear that the similarity between the left ring fingerprint from the "Little List" letter and Presidio Heights crime scene did not extend to any database search results, that included subjects such as Arthur Leigh Allen, who quite frankly should have been removed from the suspect list decades ago. All of the eight latent fingerprints retrieved from the "Little List" letter were compared to "suspects" in the Zodiac case and no match was effected. 

Dion Walker summed everything up nicely, stating "Is it really so much of a stretch - so hard to believe - that it's probable for two latent fingerprints from two different surfaces, that had both been checked against elimination prints - and were almost certainly touched by the exact same man - were similar because they were left by the same man. I think it makes sense looking at the whole picture". If the left ring fingerprint of a "suspect" exhibited similarity to the left ring fingerprint from the "Little List" letter, which itself showed a similarity to the one retrieved from the tacicab of Paul Stine, this would be our starting point. The remaining seven latent fingerprints from the same letter could then be used to compare to other digits from the "suspect", which should reasonably effect an identification (or not) of the man who masqueraded as the elusive Zodiac Killer.
​I would like to again thank Dion and Cragle for tackling this extremely labor intensive subject, and for three of the images used in the above presentation.

SEARCHING FOR THE PRINTS OF ZODIAC 
AN INITIAL CUT TO THE LEFT SIDE [PART ONE]
AN INITIAL CUT TO THE LEFT SIDE [PART TWO]

The Zodiac Killer mailed a threat to the San Francisco Examiner on July 31st 1969 stating "I want you to print this cipher on the frunt page by Fry afternoon Aug 1-69. If you do not print this cipher, I will go on a kill rampage Fry night". The murderer of three would use the word "Fry" six times and the word "print" five times in his trinity of letters, that included the San Francisco Chronicle and Vallejo Times-Herald. He claimed that he would "kill Fry night" if his cipher wasn't printed "by Fry afternoon".

Therefore, it isn't a great leap of faith that immediately following the demand of "you better print" on the December 16th 1969 "Fairfield" letter to the San Francisco Examiner, his 5 character code with one repeating symbol at position 3 and 5 contained "By" and "Fry". However, to satisfy the code the words would have to be reversed to "Fry" and "By". Bearing in mind that the Fairfield letter was postmarked on Tuesday, December 16th 1969, the Zodiac Killer's threat of "you better print Fry" would have given the newspaper three days to comply, as opposed to the one day he gave the newspapers on Thursday, July 31st 1969  Had investigators similarly concluded that "Fry" was the first word of the code, then the word "By" would have been the inevitable answer to the final two characters. 

​Both Fairfield letters in December threatened to murder "cops". The December 7th 1969 letter stated "I will kill again, so expect it any time the will be a cop". While the December 16th 1969 letter gave us a list of locations he would kill 38 cops, which included San Francisco (3), San Jose (1), Vallejo (6), Napa (8), Fairfield (3), Sacramento (9) and Oakland (8). If the initial part of the 5 character code on December 16th 1969 had read "Fry", then the introduction of "you better print" would have completed the phrase to "you better print Fry".

​Obviously, a failure to comply to his instructions of printing the 5 character code had consequences, just like on July 31st 1969, when he demanded compliance that his cipher be printed in the newspapers or he would kill a dozen people over the weekend. The San Francisco Examiner did not publish the Zodiac Killer's letter by Friday, December 19th 1969, so it probably comes as no surprise that on December 19th 1969 the Zodiac Killer made a phone call to Shirley Searey of the San Jose Highway Patrol on Friday night (10:10pm), stating "I am going to kill five of you officers and a family of five between now and Monday". The vicious verbal assault on police continued. This late night threat on Friday, December 19th 1969 to kill 10 people in total over the weekend, somewhat validates the threat of "you better print Fry" on December 16th 1969. It also mirrored the Zodiac Killer promises on July 31st 1969 to go on a "kill rampage" Friday night if his cipher wasn't printed in the newspapers. 

The threat to target 38 cops on December 16th 1969 (including in San Jose for the first time) was reinforced by the pledge to kill 5 cops over the weekend beginning December 19th 1969, when the Zodiac Killer phoned Shirley Searey at the San Jose Highway Patrol office and threatened murder between now (10:10pm) and Monday..

​The next part of the Fairfield letter code on December 16th 1969 may have contained the word "By", when you consider the yet-to-be-mailed Halloween card on October 27th 1970. The configuration of 4 offerings in 4 quadrants within both communications, possibly contained the common thread of "By". This word also satisfied the repeating symbol at position 3 and 5 of the code. The notion that Zodiac's message read "you better print Fry" or he would "By Gun, Rope, Knife and Fire" kill multiple cops at various locations, appeared to materialize when he issued the phone threat on Friday, December 19th 1969. This phone call made to the San Jose Highway Patrol should be of interest because the Fairfield letter had not yet been published in the newspapers. The phone caller at 10:10pm on Friday (if not the same person as the letter writer) couldn't possibly have known that a Friday threat was issued on December 16th 1969 (assuming the decoding is correct).

Joe Stine, the brother of the murdered taxicab driver Paul Stine, issued a confrontational challenge to the Zodiac Killer on October 23rd 1969, daring him to pay him a visit to his workplace in Modesto. Therefore, if the Zodiac Killer had the concept of By Gun, By Rope, By Knife and By Fire​ in his mind on December 16th 1969 (partly demonstrated by the car door at Lake Berryessa), it would have been extremely noteworthy that the next crime linked to him via the testimony of Kathleen Johns on March 22nd 1970 involved the burning of her vehicle "by fire" in Modesto. The Zodiac Killer told us he was starting a "little list" on July 24th 1970, owning up to the abduction of Kathleen Johns and the burning of her car, which was accompanied by the "Little List" letter two days later. Three months later he placed By Gun, By Rope, By Knife and By Fire on the back face of the Halloween card in a clockwise fashion, mimicking the order he presented his "killing tools" through time. 

The term "fingerprint of value" can refer to the evidential value of a physical fingerprint in forensic science. A "fingerprint of value" refers to a latent fingerprint impression that has enough quality and detail for a forensic examiner to make a reliable identification or exclusion. This is determined by factors like the clarity, quantity, and relationship of features within the print. While sometimes a full print is left, a partial or smudged print can still be of value if it contains sufficient information for a comparison. Evidential value refers to how useful a fingerprint is as evidence. A high-quality print with clear minutiae points (unique ridge characteristics) has a high value for comparison and identification.

​When the Zodiac Killer delivered his three-page letter to the San Francisco Examiner on the morning of August 4th 1969, he did it by hand at the newspapers offices located on Third & Market streets. The FBI files made no mention of an envelope, which is why they described the Zodiac Killer three-page letter as "undated" and never gave a mailing location. It is fairly clear at this point that the Zodiac Killer placed the three pages together and folded them at least twice, in such a way, that the third page with the Zodiac crosshairs and wording "no address" faced the receiver. Having just been sent a letter from the Zodiac Killer a matter of days earlier (on July 31st 1969) adorned with the crosshairs symbol, the Zodiac Killer was obviously highlighting a recognisable feature to the San Francisco Examiner to prioritize this communication. 

The above FBI file noted "one latent fingerprint of value developed on second page of letter (Q2), and one latent fingerprint of value developed on third page of letter (Q3)". This doesn't necessarily tell us how many fingerprints were noted on the pages, only that two of "value" were retrieved to enable a search through the extortion section of their single fingerprint file. One might expect the inner pages of an automatically manufactured writing pad to be fingerprint free, and for the Zodiac Killer to have been careful when writing on these three sheets of paper. Of course, when this folded communication was handled by the receiver, they would have certainly touched the outer third page and possibly second page when separating the three-page communication, but this person (and any subsequent handler of the pages) could easily have been eliminated as the donor of the two "fingerprints of value" collected from Q2 and Q3.

​It can be argued that these two "fingerprints of value" did not belong to any San Francisco Examiner staff, because had they, there would have been no need to put them through the extortion file search to seek a match. Therefore, these latent fingerprints were likely deposited on the two pages prior to their arrival at the San Francisco Examiner offices. If they weren't deposited on the pages during the manufacturing process, who would have touched these blank pages prior to the Zodiac Killer writing on them, other than the Bay Area murderer himself? If these two latent fingerprints on two separate pages had matched one another and not any San Francisco Examiner worker, it would have been of greater significance. Two separate digit impressions from the killer in 1969, not so much.    

The Zodiac Killer envelopes in this case had the possibility of being touched by any number of people on their journey to the newspapers, but once opened or recognised in advance as Zodiac, those individuals who have touched the writing paper itself should be identifiable, limited or non-existent. This should make any remaining and unaccounted "fingerprints of value" on the surface of any pages highly relevant in the search for the Zodiac Killer. If we have two confirmed Zodiac communications containing "fingerprints of value" on the writing pages of each (with elimination prints done), who could have donated these fingerprints in absence of the Zodiac Killer, who likely had exclusive access to his notepad? This becomes more significant on Zodiac communications mailed with multiple sheets, where less reason exists for fingerprints other than the killer to be present on page 2, 3 or 4 of any notebook or writing pad. In other words, inner pages protected by page one (from any family or friends).

There has long been interest in the comparison of prints from the taxicab of Paul Stine to the "Little List" letter mailed on July 26th 1970, and whether they originate from one individual. The "Little List" letter was a five-page offering presumably stacked in order within the envelope, so that anybody removing the contents should only reasonably have handled the front folded sheet of page 1 (the side with the introduction of "This is the Zodiac speaking"), or the rear of page 5 which was blank. There would have been absolutely no need to further contaminate the remainder of the communication with unnecessary fingerprints, bearing in mind the San Francisco Chronicle, should at this juncture, have been well versed by Zodiac investigators on how to handle Zodiac communications. There should have been no reason to touch pages 2, 3 or 4 (without gloves or at all), once the receiver had read the Zodiac introduction on page 1, assuming it wasn't recognised as a Zodiac communication before opening the envelope. Any fingerprints on pages 2, 3, 4 or 5, protected by page 1 of any writing pad (and excluding newspaper staff) should therefore be of increased importance to investigators. These pages were presumably written on consecutively by the Zodiac Killer - and as such - should not have been contaminated by hands other than the author. The page location and position of the latent fingerprint on the "Little List" letter should be factored into this equation.       . 

There remains a possibility that the latent fingerprints recovered from Zodiac communications originate from the killer, but from different digits of either hand, or different areas of the same digit, So there could be "fingerprints of value" donated by the Zodiac Killer on a single letter (or many letters), but never from the same area of a particular digit. This may explain why people say there are no definitive fingerprints of the Zodiac Killer. But this could soon change, when it becomes possible to link different digit fingerprints to the same person.

"Columbia engineers have built a new AI that shatters a long-held belief in forensics–that fingerprints from different fingers of the same person are unique. It turns out they are similar, only we’ve been comparing fingerprints the wrong way. A team led by Columbia Engineering undergraduate senior Gabe Guo challenged this widely held presumption. Guo, who had no prior knowledge of forensics, found a public U.S. government database of some 60,000 fingerprints and fed them in pairs into an artificial intelligence-based system known as a deep contrastive network. Sometimes the pairs belonged to the same person (but different fingers), and sometimes they belonged to different people. Over time, the AI system, which the team designed by modifying a state-of-the-art framework, got better at telling when seemingly unique fingerprints belonged to the same person and when they didn’t. The accuracy for a single pair reached 77%. When multiple pairs were presented, the accuracy shot significantly higher, potentially increasing current forensic efficiency by more than tenfold". Engineering Columbia Edu. 

With the advent of artificial intelligence and its possible application to the Zodiac Killer case, including the research by Columbia engineers on fingerprint comparison, we may be able to place multiple fingerprints from Zodiac letters and crime scenes into a computer, and confidentiality present an argument that some belong to one author, and ultimately one killer. Even though the fingerprints are different between the digits of one individual, they may very well be unique in design when looking at the angles and curvature of fingerprint patterns. This new concept has the potential to push the Zodiac case significantly forward in so many ways.    

There are only four communications from July 31st 1969 to January 29th 1974 where the Zodiac Killer teased us with his identity or name. The letter to the San Francisco Chronicle on July 31st 1969 promised that "in this cipher is my idenity", but only gave us 18 characters that seemingly have no discernible message. The April 20th 1970 letter with a thirteen character code tempted us with "my name is". The October 27th 1970 "Halloween" card began with the message "I feel it in my bones you ache to know my name. And so I'll clue you in". And finally, the January 29th 1974 "Exorcist" letter substituted part of the "Tit-Willow" verse for a signature, by introducing the verse with "Signed, yours truley". The Zodiac Killer teased us in each instance - yet to this day - no common thread has been found linking all four Zodiac offerings together. However, the following presentation will serve up the same "identity" in all four communications. An identity (if correct)  that would clearly have been chosen as a joke.
​
The first is incredibly tenuous, but it does exist. The deciphered portion of the 408 cipher mailed to the San Francisco Chronicle on July 31st 1969 gave us 18 letters of illegible text, yet within these 18 apparently meaningless letters the Zodiac Killer may have placed his signature, shown inside the yellow rectangle below. This suggestion is wholly unconvincing on its own, but hopefully the remainder of this analysis will maybe change your mind.

The April 20th 1970 "13-Symbol" code letter, I have argued had the key of 888, derived from the murderer's pseudonym in the 340 cipher (see here), which when applied to the Z13 code with a right shift of 8, gave us the signature of "ME ⊕" ("ME" followed by the Zodiac crosshairs). In other words, when cycling 8 positions to the right from each "circled 8", we get the signature of "ME" and his "gunsight" logo.

​If the Halloween card on October 27th 1970 was going to give us the answer of "ME" proposed in the 408 cipher and Z13 code, you would expect to find this word embedded in its design. Not only was the word "ME" curiously obvious in the Halloween card inner, it was present twice. The Zodiac Killer was clearly employing the eye in the knothole of the tree as himself, by surrounding the knothole with the ominous threat of "Peek-a-boo you are doomed".

But there is one striking feature about the writing on the tree. After the phrase "PEEK-A-BOO" the Zodiac Killer positions the word "DOOMED", such that the "ME" lines up with "PEEK-A-BOO" to create "PEEK-A-BOO, ME". It is definitely noticeable that the word "ME" is visibly larger and bolder than the rest of the writing, as if to place emphasis on this pronoun. The skeleton's left arm is also affixed to the Halloween card in such a manner that it separates the word "GAME" to spell "ME". The word "BOO" is written on the card inner at a 45 degree angle so that it too lines up with the word "ME".

The word "BOO" around the knothole and the word "BOO" to the immediate left of the skeleton, are both positioned in alignment with the word "ME". Was the Zodiac Killer giving us the answer of "ME" to "I feel it in my bones you ache to know my name. And so I'll clue you in"? Thereby replicating the answer of "ME" possibly given by the proposed solution to the Z13 code on April 20th 1970. And the signature of "ME" sitting innocuously within the 18 characters of the 408 cipher.

Finally, on January 29th 1974, the Zodiac Killer probably got tired of playing games and outright gave us his signature in plain sight, by writing "Me - 37". In fact, he effectively gave us the signature of "Me" (or "ME") a total of three times in the "Exorcist" letter. The first, as already explained, sat alongside his running victim count. The second was in the words "Signed, yours truley", because while it is often used in formal and semi-formal correspondence, in some specific contexts, it can also be used humorously or self-referentially in conversation to mean "myself". The signature of "yours truly" simply means "me". The third can be shown by using the "Tit-Willow" verse that followed "Signed, yours truley".

When we look at the Exorcist letter mailed on January 29th 1974, the Zodiac Killer appears to add the "Tit-Willow" verse from "The Mikado" for no apparent reason. However, the verse was preceded by "Signed, yours truley;" and may suggest that his identity of "Me" should be found somewhere within the verse. This concept hit a roadblock, until I looked up the following line from the complete song. The Zodiac Killer plagiarised the section below (marked in red) to place into his letter. The next line in the below verse (marked in blue) reads, in part, "Now I feel just as sure as I'm sure that my name Is". which the Zodiac Killer wrote on April 20th 1970 to introduce his Z13 code, that has already been shown to easily create the signature of "ME" and his crosshairs. Therefore, we have the "Exorcist" letter with a signature of "Me -37", the phrase of "yours truley" which means "me", introducing a "Tit-Willow" verse whose next line contains "my name is", that preceded the Zodiac Killer's Z13 code, which by using the three circled 8's as a mathematical tool, easily creates the signature of "ME". A "Tit-Willow" verse, by the way, which is split into three sections of eight lines, just like the 408 cipher. 

​July 31st 1969: "I will not give you my name because you will try to slow down or stop my collecting of slaves for my afterlife", but "in this cipher is my identity". EBEORIETEMETHHPITI.

August 4th 1969: "By the way, are the police having a good time with the code? If not, tell them to cheer up; when they do crack it, they will have me".