The Zodiac Killer appeared to be using Mount Diablo as a reference point as early as November 9th 1969, when he mailed the Bus Bomb letter and supplied us with some crosshairs and five X's on its circumference. Using this diagram it is possible to determine that the Zodiac Killer was identifying Mount Diablo as his initial or center point. Mount Diablo was used for the purpose of land boundaries in the majority of Northern California and Nevada, with the summit used as the "initial point", the north/south meridian and the east/west baseline intersection point. However, because of the vastness of California, surveying required three "initial points" of Mount Diablo, Mount Pierce and the San Bernardino Mountain to form grid lines. The Zodiac Killer knew the prominence of Mount Diablo from an elevation standpoint, but very likely knew some of the history from a navigational perspective  - and why he chose this mountain as his "initial point".

In the Dripping Pen card the Zodiac Killer was claiming the brutal stabbings of Kathie Reyne Snoozy & Debra Gaye Furlong on August 3rd 1969. On November 12th 1969, somebody featured in the San Francisco Chronicle used the San Jose double murder in their analysis of the Bus Bomb letter crosshairs, very likely concluding the "initial point" was Mount Diablo, without actually referring to the mountain by name. When you look at the five X's around the circumference, it's fairly obvious that they all sit on the left side of the crosshairs center (from 180 degrees to 330 degrees). They were positioned at 6, 8, 9, 10 and 11 on a clock face. Therefore, the "initial point" must be to the east of all the confirmed attack sites. When we attempt to line up the uppermost X with the Zodiac Killer's uppermost crime at Lake Berryessa, it becomes quickly apparent that only one position satisfies four of the X's on the circumference, and that one X represents both Lake Herman Road and Blue Rock Springs. If we draw a line through the Lake Herman Road and Blue Rock Springs attack sites, the line passes directly over the summit of Mount Diablo and beyond. By moving the crosshairs "initial point" along this line, we can see that only one position satisfies at least four of the X's.     

The Zodiac Killer only gave us a rough drawing of his crosshairs, so any interpretation must take this into account. The above diagram, centered over Mount Diablo, lines up the five locations the Zodiac Killer was claiming as his murders (Lake Herman Road, Blue Rock Springs, Lake Berryessa, San Francisco and San Jose). The (unaccounted for) red line above, travels directly over the Salesian High School of Daniel Williams, who Zodiac targeted from October 23rd 1969 to November 5th 1969 by prowling his house, poisoning his drink, making malicious phone calls, and threatening to shoot him via the Martinez Police Department. His subtle threats continued in the Dripping Pen card and Bus Bomb letter, explained thoroughly in the article The Quest For Number Eight. This is why he wrote "PS. Be Shure to print the part I marked out on page 3 or I shall do my thing" next to the crosshairs on the Bus Bomb letter. That "thing" was a threatened attack on Salesian High School, depicted by the red line on the map. The orange line shows Magnetic North of 16.5 to 17.0 degrees in 1969. The tilted crosshairs are slightly shy of this mark. But remember, the Zodiac Killer only drew us a rough guide in his correspondence. These Bus Bomb crosshairs were the precursor to the Mount Diablo map on June 26th 1970, when the Zodiac Killer again used the mountain's "initial point" as a directional tool, but this time to locate a proposed bus bomb on the Southern Freeway by Ingleside Police Station, using four radians and five inches. The Mount Diablo Map and Code Solution.     

The Zodiac Killer's 38 character code may be solved by examining three of his other ciphers (two solved and one unsolved), including the day he mailed the first Fairfield letter in December. The Z340 (November 8th 1969), Z38 (December 7th 1969), Z13 (April 20th 1970) and Z148 (probably May 3rd 1971) all have one other date in common - October 22nd 1969.

[1] The Z340 (November 8th 1969) was a response to the October 22nd 1969 Jim Dunbar Show, stating that the person who phoned into the show was effectively an imposter or phony, encoding a contemporary message and using wording similar to the headlines in the San Francisco Chronicle on October 24th 1969. The 340 message read, in part "That wasn't me on the TV Show", mimicking the headlines of "That Wasn't Zodiac, Say 3 Who Know" and "It Wasn't Zodiac, Say 3 Who Know". He also responded to the Jim Dunbar Show and the October 23rd 1969 Chronicle article, entitled "A TV Runaround With Zodiac Calls", in which "Belli told Sam he'd attempt to get a promise from District Attorney John J. Ferdon that Zodiac would be spared the gas chamber if convicted of murder". The Zodiac Killer responded in code that he was "not afraid of the gas chamber".​ 

​[2] The Z148 code (probably mailed May 3rd 1971) was again contemporary in nature, and a response to the police arrest and interview of Karl Francis Werner on April 29th 1971. Three newspaper articles ran with the headlines "San Jose Student Held in Slaying of Three Girls", "San Jose Student Held in Slaying of 3 Girls" and "Youth Arraigned in Knife Slayings of Three Girls". The Zodiac Killer encoded these headlines in his 148 character cipher by promising to "skin three kids and make a suit from the skin" if his latest letter was not published. He also encoded the statement "stop listening to phonys" in the Z148, referring to both Karl Francis Werner (who was being interviewed for the Snoozy & Furlong murders on August 3rd 1969, to which the Zodiac Killer had already claimed as his victims) and Eric Weill (who phoned into the Jim Dunbar Show at least twice, claiming to be Zodiac}. The second phone call was reported in San Francisco Chronicle on February 6th 1970, entitled "Talk Show's 'Zodiac' Caller a Phony", with Inspector David Toschi pitching in: "Homicide detectives later listened to a tape recording of the conversation and concluded that Sam was a phony. It most certainly was not Zodiac, said Inspector David Toschi".  The headlines of the October 24th 1969 and February 6th 1970 Chronicle articles both placed within the encoded text of the Z340 and Z148.

[3] The Zodiac Killer mailed the Z13 on April 20th 1970, very likely a response to the October 22nd 1969 article in the San Francisco Examiner, entitled "Cipher Expert Dares Zodiac to Tell Name". It read "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, which will truly and honestly include his name". The Zodiac responded on April 20th 1970 by stating "This is the Zodiac speaking. By the way have you cracked the last cipher I sent you? My name is___ " The letters N, A, M and E could be found in the ciphertext of the code.

[4] The Z38 mailed on December 7th 1969 began with "This is the Zodiac speaking. I just need help", mimicking the caller (Eric Weill) to the Jim Dunbar Show on October 22nd 1969. It is clear that this cry for help was a disingenuous attempt at ridicule from a killer who either listened to the Jim Dunbar Show on October 22nd 1969, or read the subsequent newspaper articles. On October 22nd 1969, the Los Angeles Times reported that "Belli was put on the line, and the voice said "I want help". On October 23rd 1969, the Desert Sun newspaper claimed that Melvin Belli told the caller “All of San Francisco wants to help you. The hand is out, you can feel the hands out.” On the same day of December 7th 1969, we have a man mailing a letter to the San Francisco Chronicle mocking the call to the Jim Dunbar Show by stating "I just need help", followed a few hours later by a call to an Oklahoma radio station by a man doing an awfully good impression of the man who rang the Jim Dunbar Show on October 22nd 1969. This impressionist caller could possibly be the Zodiac Killer mocking the Jim Dunbar Show, just as he had done in the letter earlier that day.

​Therefore, we have the Z340 (November 8th 1969), Z38 (December 7th 1969), Z13 (April 20th 1970) and Z148 (probably May 3rd 1971), all relevant to the date of October 22nd 1969. Bearing in mind the Z38 carried the same four and five characters from the beginning and the end of the 340 cipher, along with the observations above, we could expect the Z38 message to be somehow related to these other ciphers. The message may very well lie in the newspaper inches from October 22nd 1969 to December 7th 1969 - and may be related to the Jim Dunbar TV Show yet again. 

Just a quick recap: ​The author of the 38 character code prominently featured two sections of the 340 cipher, that included the beginning 4 ciphertext characters of the 340 cipher, and the last 5 ciphertext characters of the 340 cipher. The only logical reason for the Zodiac Killer to have done this, would have been to give us a clue to the solving of the 340 cipher. When the code key is applied to the 340 cipher before any period 19 (diagonal shift), the first 4 plaintext characters of the 340 cipher spell IRON. The last 5 plaintext characters spell DEATH. As previously pointed out, a hoaxer would have had to be extremely lucky to keep the beginning and ending of the 340 cipher intact, to the tune of 4 & 5 characters (when creating the Z38), that just happened to create two English words in these notable positions. One would have expected a lazy hoaxer to replicate ciphertext characters 333 to 338 in the 340 cipher, because these characters were close to the spelling of "Zodiac". But the author of the December 7th 1969 letter refrained from doing this, choosing to separate these 6 ciphertext characters, so as to form the word DEATH at the end of the 38 character code. See here.

The red rectangle above (around the first three rows of the Z38 code) represents the first 18 rows of the Z340 cipher, These sections both begin with the letter H and end with the number 9 (or reversed P), The last line in the red rectangle contains five characters, all of which can be found on the last line of the 340 cipher (that is solved only using the period 19 diagonal shift). If you apply the period 19 shift to the red rectangle of the Z38, you get H+, mirroring the first two characters seen when you apply the period 19 shift to the 340 ciphertext.  The blue rectangle (around the last two rows of the Z38 code) represents the last two rows of the Z340 (solved absent of the period 19 diagonal shift). The final five characters in the blue rectangle spell DEATH when using the 340 code key. The author of the December 7th 1969 letter (containing the Z38 code) also predated the appeal to Melvin Belli by stating "I just need help". The Zodiac Killer could not have copied the December 7th letter because it was unpublished by the time the Melvin Belli letter was mailed on December 20th 1969. It is such a shame that the majority of the Zodiac community dismiss this communication (and its sister communication on December 16th 1969) based on their extensive research of "it doesn't look like a Zodiac letter". A great opportunity to reveal another Zodiac message is sadly being ignored.  

On December 3rd 2020 David Oranchak, Sam Blake and Jarl Van Eycke unlocked the mystery to the 51-year-old 340 cipher, mailed by the Zodiac Killer on November 8th 1969. On December 7th 1969, the Zodiac Killer mailed a communication from Fairfield containing a 38 character code, yet to be broken. In recent years I have had little doubt that this letter was genuine Zodiac material, but the solving of the 340 cipher put to rest any lingering doubt regarding its authenticity.

​The author of the 38 character code prominently featured two sections of the 340 cipher, that included the beginning 4 ciphertext characters of the 340 cipher, and the last 5 ciphertext characters of the 340 cipher. The only logical reason for the Zodiac Killer to have done this, would have been to give us a clue to the solving of the 340 cipher. When the code key is applied to the 340 cipher before any period 19 (diagonal shift), the first 4 plaintext characters of the 340 cipher spell IRON. The last 5 plaintext characters spell DEATH. As previously pointed out, a hoaxer would have had to be extremely lucky to keep the beginning and ending of the 340 cipher intact, to the tune of 4 & 5 characters (when creating the Z38), that just happened to create two English words in these notable positions. One would have expected a lazy hoaxer to replicate ciphertext characters 333 to 338 in the 340 cipher, because these characters were close to the spelling of "Zodiac". But the author of the December 7th 1969 letter refrained from doing this, choosing to separate these 6 ciphertext characters, so as to form the word DEATH at the end of the 38 character code. 

After the solving of the 408 and 340 cryptograms in 1969 and 2020, there is a strong argument to be had, that the Zodiac Killer's remaining unbroken codes also contain a message, which includes the Z38 mailed just one month after the 340 cipher. I have attempted to tackle the Z38 code, but it needs an expert in code breaking to take a look at this encipherment, such as Dave Oranchak, who I believe could shed more light on this small code. The message beneath - at the very least - should provide a little more insight into the thinking of the Zodiac Killer during this crucial period. 

Did the Zodiac Killer create the 38 character code so soon after his November 8th 1969 offering as a prompt to the solution of the 340 cipher? I hope Dave Oranchak will take a look and possibly correct some of the incorrect assumptions I may have made. Thanks to Druzer, a regular contributor to both main Zodiac forums, for his assistance in this matter.
CLICK HERE FOR UNOBSTRUCTED VIEW OF CODE.

On December 3rd 2020 David Oranchak, Sam Blake and Jarl Van Eycke unlocked the mystery to the 51-year-old 340 cipher, mailed by the Zodiac Killer on November 8th 1969.  The decoded message was a response to the Jim Dunbar Show in which an imposter/fraud called in to the TV show pretending to be the infamous Zodiac Killer.on October 22rd 1969. It may have also been a response to the San Francisco Chronicle article on October 23rd 1969 entitled A TV Runaround With Zodiac Calls in which "Belli told Sam he'd attempt to get a promise from District Attorney John J. Ferdon that Zodiac would be spared the gas chamber if convicted of murder". The Zodiac Killer responded in code that he was "not afraid of the gas chamber". 

The following day, the San Francisco Chronicle published another article which featured the opinions of Nancy Slover, David Slaight and Bryan Hartnell, who were the only three people credited with hearing the Zodiac's voice to date. The headline of that column read That Wasn't Zodiac, Say 3 Who Know, to which the Zodiac Killer would reply in his message in the 340 cipher by confirming "That wasn't me on the TV show". He took the newspaper headline and incorporated it into his hidden message. The Zodiac Killer was effectively rejecting the notion that the person who appeared on the Jim Dunbar Show claiming to be him was the genuine article - the caller was a fraud or imposter.

The decoded 340 ciphertext read: I HOPE YOU ARE HAVING LOTS OF FUN IN TRYING TO CATCH ME - THAT WASN’T ME ON THE TV SHOW - WHICH BRINGS UP A POINT ABOUT ME - I AM NOT AFRAID OF THE GAS CHAMBER BECAUSE IT WILL SEND ME TO PARADICE ALL THE SOONER BECAUSE I NOW HAVE ENOUGH SLAVES TO WORK FOR ME WHERE EVERYONE ELSE HAS NOTHING WHEN THEY REACH PARADICE - SO THEY ARE AFRAID OF DEATH - I AM NOT AFRAID BECAUSE I KNOW THAT MY NEW LIFE IS LIFE WILL BE AN EASY ONE IN PARADICE DEATH.

However, it didn't stop there. On February 5th 1970, the Desert Sun newspaper reported that "a man claiming to be the Zodiac killer of five persons held another on-the-air conversation today with television personality Jim Dunbar. Two police inspectors closeted themselves with Dunbar at station KGOTV immediately after the one-sided conversation, which consisted mainly of Dunbar asking questions and repealing fragments of answers". This second call was also reported in the San Francisco Chronicle on February 6th 1970, again highlighting the belief of investigators that this person was another fraud impersonating the Zodiac Killer. Just over a year later the Zodiac Killer mailed a 148 character cryptogram and letter, again encoding a contemporary message, but this time calling out Karl Francis Werner as a phony. Karl Francis Werner had just been arrested in connection with the murders of Kathie Reyne Snoozy, Debra Gaye Furlong and Kathy Bilek, two of which he had long claimed he murdered since the mailing of his November 8th 1969 Dripping Pen card and 340 cryptogram. He would also soon claim Kathy Bilek as a murder victim in the July 13th 1971 Monticello card. The Zodiac Killer was clearly upset somebody else had been arrested for the two San Jose murders on August 3rd 1969 and was responding to a San Francisco Chronicle article on April 30th 1971 entitled San Jose Student Held in Slaying of Three Girls. The newspaper article read "He was immediately advised of his rights concerning any statements he may make and legal representation to which he is entitled, the detectives said. Werner was then taken to the scenes of the crimes. Late yesterday he was undergoing questioning. The detectives would not reveal what statements, if any, he had made concerning the killings of the three girls". His response was immediate, likely firing off the following communication in early May. 

The Zodiac Killer was responding to the Paul Avery newspaper article on April 30th 1971 describing the arrest and interview of Karl Francis Werner by law enforcement, imploring investigators to "stop listening to phonys". Just like the 340 cipher, in which the Zodiac Killer used the newspaper headline banner of That Wasn't Zodiac, Say 3 Who Know to create "That wasn't me on the TV show", he would again use a newspaper headline banner in his rebuttal of Karl Francis Werner as the killer of the three girls (in particular, Snoozy & Furlong).

An imposter/fraud had called into the Jim Dunbar TV Show on October 22nd 1969, followed by a second call to the show on February 5th 1970. The San Francisco Chronicle article on the left was entitled Talk Show's Zodiac Caller Called a Phony. The article read "Homicide detectives later listened to a tape recording of the conversation and concluded that Sam was a phony. It most certainly was not Zodiac, said Inspector David Toschi".  Fast forward to May of 1971, in which Karl Francis Werner is being interviewed by investigators for three murders, including the brutal stabbings of Kathie Reyne Snoozy and Debra Gaye Furlong, to which Zodiac had previously claimed by the addition of "Aug" on his November 8th 1969 Dripping Pen card. Perceived by him, the Zodiac Killer has now had the indignity of two phone calls to the Jim Dunbar Show, where a phony has effectively claimed his crimes, followed by the arrest and interview of Karl Francis Werner in 1971, possibly being credited with crimes he had previously claimed. His response to law enforcement was "stop listening to phonys", again using a newspaper headline incorporated into the ciphertext message of his cryptogram.

At the time the Zodiac Killer mailed the 148 character cipher in 1971, the 340 cryptogram was unsolved. Yet here we have two lengthy cryptograms, both of which are incorporating in contemporary form the rejection of an imposter or phony by using the phrases "That wasn't me on the TV show" and "stop listening to phonys" - and both cryptograms incorporated the language used in two newspaper headlines.

The 340 and 148 character cryptograms are inextricably linked through a message that is contemporary in nature, both are the rejection of two people connected to his crimes (and claimed crime), and both the Dripping Pen card and 148 character cipher are indelibly linked to the murders of Kathy Reyne Snoozy and Debra Gaye Furlong who were horribly killed and mutilated on August 3rd 1969 in San Jose. The Zodiac Killer would finish his written message in May 1971 with the wording of "I will send a patch of human skin if their is some left over". This was a threat to kill another three kids, just like Snoozy, Furlong and Bilek. The nature of these three brutal stabbings (in excess of 300 knife wounds) should leave you in no doubt the meaning behind the sinister message of "I will send a patch of human skin if their is some left over".

On December 3rd 2020, Dave Oranchak (USA), Sam Blake (Australia) and Jarl Van Eycke (Belgium) finally unearthed the solution to the 340 cipher after 51 years. The message read:

I HOPE YOU ARE HAVING LOTS OF FUN IN TRYING TO CATCH ME - THAT WASN’T ME ON THE TV SHOW - WHICH BRINGS UP A POINT ABOUT ME - I AM NOT AFRAID OF THE GAS CHAMBER BECAUSE IT WILL SEND ME TO PARADICE ALL THE SOONER BECAUSE I NOW HAVE ENOUGH SLAVES TO WORK FOR ME WHERE EVERYONE ELSE HAS NOTHING WHEN THEY REACH PARADICE - SO THEY ARE AFRAID OF DEATH - I AM NOT AFRAID BECAUSE I KNOW THAT MY NEW LIFE IS LIFE WILL BE AN EASY ONE IN PARADICE DEATH.
Here is what the Zodiac Killer could have written regarding the phone call to the Jim Dunbar Show:
I HOPE YOU ARE HAVING LOTS OF FUN IN TRYING TO CATCH ME - STOP LISTENING TO PHONYS - WHICH BRINGS UP A POINT ABOUT ME - I AM NOT AFRAID OF THE GAS CHAMBER BECAUSE IT WILL SEND ME TO PARADICE ALL THE SOONER BECAUSE I NOW HAVE ENOUGH SLAVES TO WORK FOR ME WHERE EVERYONE ELSE HAS NOTHING WHEN THEY REACH PARADICE - SO THEY ARE AFRAID OF DEATH - I AM NOT AFRAID BECAUSE I KNOW THAT MY NEW LIFE IS LIFE WILL BE AN EASY ONE IN PARADICE DEATH. 

One of the most remarkable achievements in the Zodiac story occurred in 2020, when David Oranchak, Sam Blake and Jarl Van Eycke collaborated to finally break the 51 year resistance of the infamous 340 cipher on December 3rd. But what inspired the added complexity and the diagonal shift employed by the Zodiac Killer in his encryption technique on November 8th 1969. The trigger may have been his 408 cipher and the detailed attempt to break it in the Vallejo News Chronicle on August 4th 1969, at a time when the Zodiac Killer would undoubtedly have been scrutinizing the newspapers for progress on his 408 cipher. This was pointed out to me by the forum contributor known as Cragle, who made this astute observation recently.     

The cryptogram fan from San Francisco, a graduate student, made some observations regarding the 408 cipher (shown on the left). While his analysis wasn't wholly accurate, it is this newspaper article that may have bearings on the technique employed by the Zodiac Killer when designing his 340 cipher. On page two of this newspaper article it continued The pattern beginning to take shape apparently will end up a three-tiered diagonal structure composed of sections, of each of the three ciphers. Work with the patterns of the ciphers, which he calls complex and the work of a very intelligent person, has yielded eight doublets of symbols which are equals. He remarked that he didn't feel the ciphers were a hoax because they are too complicated and required too much effort to devise. "A computer may have been used" he said. He thinks the person who made them is intelligent, scheming and imaginative, but not really unusual. "I know kids in school who could do better" on cryptograms. 

The next communication mailed by the Zodiac Killer on October 13th 1969 promised to target young children, threatening that "School children make nice targets, I think I shall wipe out a school bus some morning. Just shoot out the front tire + then pick off the kiddies as they come bouncing out". But the most important section in the Vallejo News Chronicle article was "The pattern beginning to take shape apparently will end up a three-tiered diagonal structure composed of sections". The Zodiac Killer's 340 cipher, that followed the October 13th 1969 letter, was three-tiered just like the 408 cipher, but crucially it was structured diagonally for the majority of the coding, as postulated in the newspaper. The title of the newspaper article was Text Of Letter May Offer Clues, but did it offer the inspiration for the Zodiac Killer to create a diagonal shift in his 340 cipher just three months later?

On October 22nd 1969, the San Francisco Examiner newspaper published an article by Will Stevens, which laid down a challenge from Professor D.C.B. Marsh of the American Cryptogram Association (ACA) to the Zodiac Killer, attempting to coax him into revealing 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".

Professor D.C.B. Marsh was probably hoping the Zodiac Killer would employ a cryptographic technique featured in the works of Edgar Allan Poe, thereby making any future cipher mailed by the Zodiac Killer easier to crack. As it turned out, the Zodiac Killer's 340 cipher mailed on November 8th 1969 could be solved using the scytale method of encryption detailed in Edgar Allan Poe's essay A Few Words on Secret Writing in the very first paragraph. This was covered extensively in the article The Inspiration Behind the Zodiac Killer's 340 Cipher. We have Professor D.C.B. Marsh of the American Cryptogram Association creating the trigger, by inserting Edgar Allan Poe into the mind of the Zodiac Killer. The Zodiac Killer then created the 340 cipher that could be deciphered using the scytale method featured in Poe's A Few Words on Secret Writing. What are the odds that one of Edgar Allan Poe's poems would partially appear in the solution to the 340 cipher?

I HOPE YOU ARE HAVING LOTS OF FUN IN TRYING TO CATCH ME - THAT WASN’T ME ON THE TV SHOW - WHICH BRINGS UP A POINT ABOUT ME - I AM NOT AFRAID OF THE GAS CHAMBER BECAUSE IT WILL SEND ME TO PARADICE ALL THE SOONER BECAUSE I NOW HAVE ENOUGH SLAVES TO WORK FOR ME WHERE EVERYONE ELSE HAS NOTHING WHEN THEY REACH PARADICE - SO THEY ARE AFRAID OF DEATH - I AM NOT AFRAID BECAUSE I KNOW THAT MY NEW LIFE IS LIFE WILL BE AN EASY ONE IN PARADICE DEATH.   

"To One in Paradise" was written by Edgar Allan Poe. This poem was first published as part of the short story titled "The Visionary" (later retitled as "The Assignation"). The poem was also published under the names "To lanthe in Heaven" and "To One Beloved". The title "To One in Paradise" was used in the February 25, 1843 Saturday Musuem. This poem was written after the death of Poe's wife. He writes that she was his life and he lived for her and now he looks forward to the future where they will be together again in death. link.

The breaking of the 340 cipher by David Oranchak, Sam Blake and Jarl Van Eycke on December 3rd 2020 was a fantastic achievement after 51 years, only slightly tarnished by the banality of the message encoded by the Zodiac Killer, in which he denied it was him on the Jim Dunbar Show, along with the usual paradice and slaves nonsense. However, it may have gone a long way to verifying two previous communications once considered inauthentic Zodiac letters. 

The 340 message stated "That wasn't me on the TV show", thereby suggesting by inference that the person who called into the Jim Dunbar TV show on October 22nd 1969 was an imposter and fraud. Shortly after the April 29th 1971 arrest of Karl Francis Werner for the murders of Kathie Reyne Snoozy, Debra Gaye Furlong and Kathy Bilek in San Jose and Saratoga, another cryptogram was mailed from Fairfield to the San Francisco Chronicle containing 148 characters. It too was effectively delivering a contemporary message, again claiming that the person (Karl Francis Werner) being 'interviewed' was an imposter and fraud, stating "Tis the Zodiac Speacking. Why can't you stop me. I can't stop killing. Stop listening t(o) phonys". The 340 cipher was unbroken in 1971, yet the author of another contemporary enciphered message was again claiming that the person in the spotlight was a "phony". The only difference this time was the Zodiac Killer was the "phony", falsely attempting to wrestle back the murder victims of Snoozy & Furlong on August 3rd 1969, that he had claimed in the Dripping Pen card mailed on November 8th 1969, with his addition of "Aug" in his chronological victim count of seven. He would further compound matters by adding the April 11th 1971 murder of Kathy Bilek to this list, when on July 13th 1971 he claimed her murder in the Monticello card by stating "In The Woods Dies April".

This should allay any doubts as to the authenticity of this communication, especially when you consider that the Monticello card "shought victims 21" just like the written message accompanying the 148 character cipher - and both were withheld from the newspapers.

The 340 cipher also went a long way to verifying the 38 character code, mailed from Fairfield on December 7th 1969, because both cryptograms isolated the word "death" at the end of each message. The person who created the Z38 deliberately separated the prominent ZO∆AIKꞮ+ characters on the bottom line of the 340 cipher, into AIKꞮ+ on the bottom line of the 38 character code. thereby manufacturing the word "death". Druzer, a valued contributor to both main Zodiac forums, pointed out the same thing, stating  "The most curious/compelling feats are that the author isolated actual words, most notably death, and that he refrained from copying Zodaik, which would certainly be expected of a hoaxer".  

The 340 cipher did indeed harbor a banal and relatively uninteresting message after a long 51 year wait, but it can be argued that the solving of the message contained within it, may have handed us two more confirmed Zodiac communications to examine, offering fresh insights into an investigation often blighted by stagnation. The Z38 can be connected to the 340 cipher through two notable portions of each code, The words IRON and DEATH can be found in both, before any period 19 shift is applied. If these two enciphered cryptograms are connected by beginning and end, then why should the middle section of the Z38 be any different. The Z38 and Z340 could very well be have a much bigger relationship, yet to be unearthed.

Just over two weeks before the 340 cipher was mailed, Dr. D.C.B. Marsh of the American Cryptogram Association laid down a challenge to the Zodiac in the newspapers to reveal his name in a cipher, however complicated. The wording in the San Francisco Examiner on October 22nd 1969 invoked the name of Edgar Allan Poe, so possibly the designers of the article were hoping that the Zodiac Killer would invoke Edgar Allan Poe to give us his name, making any offering easier to crack. This appeared to influence the Zodiac Killer, because the first cipher mentioned in Poe's essay A Few Words on Secret Writing actually works in decoding the message in the 340 cipher. The second cipher technique in Poe's essay A Few Words on Secret Writing split the alphabet into two portions of 13 letters, so it was surprising that the Zodiac Killer's next code reduced dramatically to 13 characters just like Poe's design (beginning with A and ending with M). See here for essay.

Three years ago, it was suggested that the Zodiac Killer wouldn't again shy away from the challenge of giving us his name, having possibly given us it in an abbreviated format. That is why the cryptic reference of Fk, I'm crackproof caught my eye in the October 5th 1970 communication with 13 punch-holes in the fabric of the card. The punch-holes were separated into a 10 to 3 configuration, positioned in such a way that they mirrored the design of the 13-Symbol cipher. The only way to break the small code was to discover the entry point, and the three circled 8's seemed as good a place as any, especially when we consider Fk, I'm crackproof is split into three parts and fits around the existing K and M in the code. The crosshairs, anchor and Celtic Cross in the code are all religious symbols, with the number 8 representing rebirth, regeneration and a new beginning in Christianity. The figure 888 is also representative of Jesus Christ in Christian numerology. It was discovered that the first 8 began FK, the second 8 began IM and the third 8 began CRACKPROOF, which completed the circle of eternal life. The introduction to the April 20th 1970 letter was also completed, to "This is the Zodiac speaking. By the way have you cracked the last cipher I sent you? My name is Fk, I'm crackproof",

Anyway, this is to show that the Fk, I'm crackproof solution was found before the 340 cipher was cracked by Dave Oranchak, Sam Blake and Jarl Van Eycke on December 3rd 2020, along with its scytale links to Edgar Allan Poe's A Few Words on Secret Writing. This is extremely important when we consider the following. Edgar Allan Poe highlighted certain encipherment techniques in the essay regarding a split alphabet, which are outlined here: and, so placed, a might stand for n and n for a, o for b and b for o, &c. &c. This, again, having an air of regularity which might be fathomed, the key alphabet might be constructed absolutely at random. The next line was: Thus A might stand for P.

These examples can be summarized as;
[1] a might stand for n and n for a
[2] Therefore, r might stand for e and e for r
[3] Thus, a might stand for p (and vice-versa)
Using only these examples in the 13-Symbol cipher, I inserted the possibilities into the code, using the letters K and M as entry points, based on the aforementioned reasoning. The letters N, A and M (not boxed in blue) I have no explanation for. So the search goes on to discover whether the Zodiac applied something else to the encryption. Or whether a different technique was used entirely.

When you take into consideration that the Fk, I'm crackproof solution was suggested in 2017, before the scytale link of the 340 cipher to Edgar Allan Poe, coupled with the formation above using just Poe's examples shown in [1], [2] and [3], it shows a pattern receptive to the remaining letters in the solution. But the three remaining ciphertext characters would need explaining. 

The next encipherment technique described in A Few Words on Secret Writing were the two concentric circles (one fixed), where the outer wheel can be rotated around the inner wheel during the coding process. Here is a working cipher wheel.

On October 22nd 1969, Dr. D.C.B Marsh in alliance with investigators and the San Francisco Examiner, attempted to refocus the Zodiac Killer's attention toward creating a second major cryptogram and "reveal his name in the cipher to established cryptogram experts". Marsh would continue to press the killer throughout the article, stating "I invite Zodiac to send to The American Cryptogram Association a cipher code - however complicated - which will truly and honestly include his name". However, in order to crack any cipher the killer may send, it would have been wise to place certain triggers within the article to guide the Zodiac Killer into choosing a particular cryptographic technique. This may have been the purpose of dropping the name Edgar Allan Poe into the San Francisco Examiner article, thereby influencing the killer to choose a cryptographic technique highlighted by Poe in one of his essays. If the Zodiac Killer then responds with a second cipher, your first port of call would obviously be Edgar Allan Poe.

Although Dave Oranchak doesn't believe the Zodiac Killer used the scytale method of encryption in the recently decoded 340 cipher, this decryption tool does actually decode the message in the 340 cipher. If the Zodiac Killer responded to the prompt by Dr. Marsh and read Edgar Allan Poe's essay A Few Words on Secret Writing, he would have noticed that the first topic of discussion was the scytale cipher, which involves disguising a message by separation, avoiding the common left-to-right method of decryption. This is what the Zodiac Killer used in his 340 cipher. In further reading of A Few Words on Secret Writing, it became apparent that other encryption methods were discussed in addition to the scytale method, with the possibility existing that the Zodiac Killer may have adopted one of these techniques for his following 13-Symbol cipher on April 20th 1970. The most notable encryption methods discussed included separating the alphabet A to M, and N to Z, into two equal parts of 13 letters. This involved placing the alphabet into the following configuration.

Here is an excerpt from Edgar Allan Poe's A Few Words on Secret Writing: and, so placed, a might stand for n and n for a, o for b and b for o, &c. &c. This, again, having an air of regularity which might be fathomed, the key alphabet might be constructed absolutely at random. The next line was: Thus A might stand for P.

If we then represent the second ciphertext character N (11th position} with the plaintext character A shown in Poe's writing, we get the diagram shown below, with the circular Fk, I'm crackproof starting to emerge.

The relationship  between the remaining ciphertext characters of N, A and M, to the plaintext characters in the solution of O, C and K respectively, can be seen in the diagram below. These are never more than two apart in the alphabet. This is a work in progress.

The Concerned Citizen card was mailed from San Francisco and postmarked August 10th 1969, arriving one day after the article A Murder Code is Broken which featured in the San Francisco Chronicle newspaper. In this article "Vallejo Police Sergeant John Lynch, in charge of the investigation of the murders and of the cipher letter writer, asked The Chronicle to send Harden's code breaking worksheets to him for further checking; which was done". The Concerned Citizen communication (with attached 408 cipher key) was not mailed by Donald Harden, having been sent from either a genuinely helpful citizen or from the Zodiac Killer himself. When deciding which is the case, we can look at the typed message on the card (shown below).

For somebody who pleasures in the solving of cryptograms and word puzzles, while at the same time making basic spelling mistakes and errors in punctuation, seems rather reminiscent of somebody we have become accustomed to. Three months after this correspondence, the Zodiac Killer mailed the infamous 340 cipher, a curious blend of both word puzzle and cryptogram. This cipher had "paradice" and "slaves" criss-crossed on its canvas, with a full message beneath the superficial design. The canvas and cipher both contained the encoded words of "paradice" and "slaves", thereby continuing the theme from the 408 cipher, but on this occasion he seemed eager to add a little more complexity to its design.

The decoding of the 340 cipher revealed that the majority of the message effectively ran diagonally (one down, two across) in a cipher divided up into three parts of 9, 9 and 2 rows. The last two rows were composed of a curious blend of forward and backward words, which is standard fare in the construction of word search puzzles, as is the creation of diagonal wording running across a word search grid. When we couple this with the disguised "paradice" and "slaves" running down and across the center of the 340 cipher canvas, this cryptogram becomes the embodiment of cipher and word puzzle all rolled into one.

If that wasn't enough, the Zodiac Killer would mail two more communications on December 10th 1969 and December 11th 1969 with coherent messages in the form of a pre-printed horoscope, overlayed with cryptic messages pasted predominantly 90 degrees clockwise, running down the page. These two communications were entitled Day-by-day forecast for Cancer and Day-by-day forecast for Leo. The second coming the day after the abduction of Leona LaRell Roberts (16) on December 10th 1969, leading to the possibility that this was a further play on words by the Zodiac Killer, who may have used the phrase "forecast for Leo" to insinuate the future plight of Leona Roberts. He may have had no hand in the abduction of Leona Roberts, but it wasn't unusual for the Zodiac Killer to insinuate his involvement in crimes committed by others. 

The two pasted communications in December (with Hidden and FLT a component of both) must have taken some forethought, so the idea that these two communications have no meaning whatsoever, doesn't quite sit right. These messages may need decoding just like the 340 cryptogram, albeit in a slightly different way. The choice of two horoscopes, when we consider the contemporary speculation behind the Zodiac Killer's choice of pseudonym, may have some significance. These two communications were straddled by both Fairfield letters, the first of which (December 7th 1969) contained sections of ciphertext that married up with the beginning and end of the 340 cipher. The months of July, November and December certainly seemed one big cryptic puzzle for the Zodiac Killer, but was it "one of his pleasures" in August. 

On October 22nd 1969, somebody rang the Oakland Police Department to request that either Francis Lee Bailey or Melvin Belli appear on the Jim Dunbar chat show at KGO Radio in San Francisco. Melvin Belli would co-host the morning show at approximately 6:30 am, to which, after a period of inactivity, an unknown male would call and hang up numerous times. The dysfunctional sounding caller claimed he was the infamous Zodiac Killer, a man responsible for at least five murders in the Bay Area of California.

Three people who had heard the Zodiac Killer's voice, Nancy Slover, David Slaight and Bryan Hartnell, were confident that the caller was not the man they had heard during their respective encounters with the killer. A fourth person was absolutely certain, because he was about to compose a 340 cipher denouncing the caller to the Jim Dunbar Show as a fraud, by stating "That wasn't me on the TV show". Many have found it strange that the Zodiac Killer decided to encode this denial, when he could have simply written it into the Dripping Pen card that accompanied the cipher. He clearly expected this cryptogram to be decoded fairly quickly as the message was contemporary, and of diminishing value as the years ticked by.

However, his method of encoding such contemporary information to highlight that it wasn't him on the TV show, thereby confirming that the Jim Dunbar Show caller was an imposter, was to be repeated eighteen months later. Another cryptogram would be mailed to the San Francisco Chronicle in about May of 1971, harboring a hidden message that was again contemporary in nature, while calling out an imposter. This time though, the tables would be turned. On this occasion, the Zodiac Killer would be calling out a "phony", when in realty he was the imposter and the person he was addressing was the real killer. This stemmed from his false claim that he was the murderer of Kathy Snoozy (15) and Deborah Furlong (14) in San Jose. These two young girls were brutally stabbed on August 3rd 1969 and claimed as Zodiac victims when he mailed the Dripping Pen card on November 8th 1969. He would write "Des, July, Aug, Sept, Oct = 7", thereby falsely inflating his victim count to engender more terror over a wider area.

On April 29th 1971, Karl Francis Werner was arrested for the murders of Kathy Snoozy, Deborah Furlong and Kathy Bilek, and his story was covered by Paul Avery on April 30th 1971 under the title of San Jose Student Held in Slaying of Three Girls. 
The newspaper article stated "He was immediately advised of his rights concerning any statements he may make and legal representation to which he is entitled, the detectives said. Werner was then taken to the scenes of the crimes. Late yesterday he was undergoing questioning. The detectives would not reveal what statements, if any, he had made concerning the killings of the three girls". The Zodiac Killer was understandably horrified, because the two murders he had falsely adopted into his victim total for a year-and-a-half, were about to be handed over to someone else. Karl Francis Werner was ultimately charged (and later convicted) of all three murders, but the Zodiac Killer was having none of it, firing off a 148 character cipher and letter sometime in May (see below).

Just like his encoded message in the 340 cipher stating "That wasn't me on the TV show", he would again encode the following message "Tis the Zodiac Speacking. Why can't you stop me. I can't stop killing. Stop listening t(o) phonys. If this is not on your front page in a week I will skin 3 little kids and make a suit from the skin". The Zodiac Killer was responding to the Paul Avery newspaper article, informing everybody that they should pay no attention to Karl Francis Werner and insisted they should "Stop listening to phonys". One can't help seeing the irony of the situation. The Zodiac Killer effectively declared that the caller to the Jim Dunbar Show was a phony because it wasn't him on the TV show, but has now become the phony calling out the real killer - and both of these declarations hidden within cryptograms separated by eighteen months. The Zodiac Killer felt angered enough to dissuade law enforcement in listening to Karl Francis Werner, yet disguised this pertinent message behind a wall of coding, just as he had done on November 8th 1969 with another contemporary message. However, there was one big difference. This latest cryptogram had returned back to the standard left-to-right homophonic technique employed by the 408 cipher. Bearing in mind his 340 cipher was yet to be deciphered - and knowing he wanted to declare Karl Francis Werner a fraud while it still mattered - the Zodiac Killer probably thought it wise to return back to the simplest form of encryption.

Early in December 2020, the 340 cipher was cracked by David Oranchak, Sam Blake and Jarl Van Eycke, which revealed the message shown below. Despite the fact the message left many rather deflated because of its banality, hoping it would reveal so much more, the message contained in the Dripping Pen card and the following Fairfield letters appear to show a running theme. It was recently highlighted how the 38 character code in the December 7th 1969 communication (1st Fairfield letter) showed a distinct correlation to the 340 cipher. Here is a brief recap:

If a Zodiac impersonator had created the 38 character code, this hoaxer would have had to guess that by separating the prominent ZO∆AIKꞮ+ characters on the bottom line of the 340 cipher, into AIKꞮ+ on the bottom line of the 38 character code, he would be reducing these characters to create something meaningful. He apparently did. By separating these characters into the five visible at the end of the 38 character code, he created the word "death", just like the solved 340 cipher. Druzer, an excellent Zodiac researcher, pointed out the same thing, stating "The most curious/compelling feats are that the author isolated actual words, most notably death, and that he refrained from copying Zodaik, which would certainly be expected of a hoaxer". In other words, he dismantled the ZO∆AIK element, while leaving Ɪ+ in place, to form "death" as the final word on the 38 character code. This appears to show knowledge of the hidden message in the 340 cipher. But there is so much more in the Fairfield letters that harks back to the Dripping Pen card and 340 cipher.

Despite stating in the above message he now had enough slaves to work for him in paradice, he would ultimately decide to "kill again" on December 7th 1969, in accompaniment to his brief 38 character code. The Zodiac Killer would never use the standalone word "life" outside of the November 8th and December 16th communications, yet he would end the 340 message with "life will be an easy one in paradice [death]", and begin the December 16th 1969 communication (2nd Fairfield letter) with "I just need to tell you this state is in troulbe, I will go for the Goverment life".

The Dripping Pen card containing the 340 cipher stated "Could you print this new cipher in your frunt page?", whereas the wording "you better print" preceded the small 5/9 character code in the December 16th 1969 letter. The decoded message in the 340 cipher (unknown to anyone until December 2020) began in mocking fashion, stating "I hope you are having lots of fun trying to catch me", while the message immediately beneath the small code in the December 16th 1969 letter stated "you will not catch me". It was almost as though the Zodiac Killer was replying to himself just over five weeks later, in absence of his cipher being solved.

On October 22nd 1969, the Oakland Police Department took a call in the early morning hours from somebody claiming to be the Zodiac, requesting that either Melvin Belli or Francis Lee Bailey, high profile lawyers at the time, appear on a chat show hosted by Jim Dunbar later that day. Melvin Belli agreed to appear on the show to which a man would eventually contact via telephone, claiming not only his name was 'Sam', but also by inference that he was the infamous Zodiac Killer. It was very quickly determined from Nancy Slover, David Slaight and Bryan Hartnell that the caller to the TV show wasn't the Zodiac Killer, which was confirmed by the decoded 340 message, which read "That wasn't me on the TV show". However, the Zodiac Killer didn't expand on who the person was that made the phone call to the Oakland Police Department. Whether he was leaving this open to speculation deliberately, nobody knows, but Oakland would feature in his murder destinations on December 16th 1969. This was the only time this city would feature by way of written text in any of the Zodiac Killer's communications, and it came just five weeks after the Bay Area murderer encoded the denial of "That wasn't me on the TV show". Was it a subtle admission that he did make the Oakland phone call to police and was now promising to murder eight of them, hence the renewed contact with Melvin Belli just four days later providing a piece of Paul Stine's shirt?

There are three things a hoaxer should not have known regarding the decoded 340 cipher message. [1] He shouldn't have known that by separating ZO∆AIKꞮ+ into AIKꞮ+ that it would produce the word "death" at the end of both codes, and provide a common link between the two. [2] He shouldn't have known that the opening line of the 340 message read "I hope you are having lots of fun trying to catch me", when he replied "you will not catch me" only 38 days later, unless you maintain that this is a coincidence. [3] He shouldn't have known that the Oakland inspired TV show had featured as a denial by the Zodiac Killer in the message, when he listed Oakland in the list of his murder sites.

The word "death" could be decoded using the Zodiac key through both the Z340 and Z38 within 29 days of one another. The December 16th 1969 letter also contained a configuration of four smaller crosshairs positioned around larger crosshairs, similar to the configuration of By Knife, By Gun, By Rope and By Fire on the Halloween card mailed on October 27th 1970. However, on this occasion the design was preceded by five characters. Could this be the word "death" once again, mirroring the Tim Holt comic book which likely inspired the design of the Halloween card in the first place? Anyway, "I thought you would nead a good laugh before you hear the bad news. Ha! Ha! Ha!"   

After two Zodiac attacks in close succession on September 27th 1969 and October 11th 1969, investigators must have feared an escalation in terror from the Bay Area murderer, so it would have certainly been in their interests to switch the Zodiac Killer's attention to communication instead of murder. On October 22nd 1969, Dr. D.C.B Marsh in alliance with investigators and the San Francisco Examiner, attempted to refocus the Zodiac Killer's attention toward creating a second major cryptogram and "reveal his name in the cipher to established cryptogram experts". Marsh would continue to press the killer throughout the article, stating "I invite Zodiac to send to The American Cryptogram Association a cipher code - however complicated - which will truly and honestly include his name". However, in order to crack any cipher the killer may send, it would have been wise to place certain triggers within the article to guide the Zodiac Killer into choosing a particular cryptographic technique. This may have been the purpose of dropping the name Edgar Allan Poe into the San Francisco Examiner article, thereby influencing the killer to choose a cryptographic technique highlighted by Poe in one of his essays. If the Zodiac Killer then responds with a second cipher, your first port of call would obviously be Edgar Allan Poe.

Although Dave Oranchak doesn't believe the Zodiac Killer used the scytale method of encryption in the recently decoded 340 cipher, this decryption tool does actually decode the message in the 340 cipher. If the Zodiac Killer responded to the prompt by Dr. Marsh and read Edgar Allan Poe's essay A Few Words on Secret Writing, he would have noticed that the first topic of discussion was the scytale cipher, which involves disguising a message by separation, avoiding the common left-to-right method of decryption. This is what the Zodiac Killer used in his 340 cipher. In further reading of A Few Words on Secret Writing, it became apparent that other encryption methods were discussed in addition to the scytale method, with the possibility existing that the Zodiac Killer may have adopted one of these techniques for his following 13-Symbol cipher on April 20th 1970. The most notable encryption methods discussed included separating the alphabet A to M, and N to Z, into two equal parts of 13 letters. Followed by a technique involving two concentric discs, akin to the Union Cipher Disk that held the number configurations of 000 and 888. These techniques show promise when we consider the design and structure of the 13-Symbol cipher. This has been covered in a much more extensive article, so it will not be covered any further here.  

Dr. Marsh, under the banner of Cipher Expert Dares Zodiac to Tell Name, would persist throughout the article into cajoling the Zodiac Killer to reveal his name by way of a cryptogram. This is why another passage in A Few Words on Secret Writing caught my attention - and may have resonated with the Zodiac Killer too. It concerned a reader sending in cryptograms to Edgar Allan Poe, but refraining from giving his name. The passage read "This challenge has elicited but a single response, which is embraced in the following letter. The only quarrel we have with the epistle, is that its writer has declined giving us his name in full. We beg that he will take an early opportunity of doing this, and thus relieve us of the chance of that suspicion which was attached to the cryptography of the weekly journal above-mentioned–the suspicion of inditing ciphers to ourselves. The postmark of the letter is Stonington, Conn".

This reminded me of the statement by Dr. Marsh when he challenged Zodiac, who he contended "had not told the truth in his cipher messages to the Examiner, the Chronicle and the Vallejo Times-Herald". He claimed "Zodiac has not done this, because to tell the complete truth in relation to his name would lead to his capture". Did the Zodiac Killer read this passage in A Few Words on Secret Writing and get some ideas?

The reader who mailed Edgar Allan Poe from Stonington, Connecticut, failed to supply his name, but did begin by placing a letter S, followed by a horizontal dash, similar to the Zodiac Killer's introduction on April 20th 1970, The Zodiac Killer began the introduction to his 13-Symbol cipher by stating MY NAME IS ---------. The sender of the cryptograms to Poe only signed his name at the bottom of the intoductory letter by use of initials, concluding with "I am yours, respectfully S.D.L." Not wanting to shy away from the challenge of Dr. Marsh a second time, I couldn't help thinking that the Zodiac Killer may have rose to the challenge and given us the initials to his name (or fictitious initials), just like the sender of the cryptograms from Stonington, Connecticut. Another thing to note, is that Dr. Marsh laid down this challenge on October 22nd 1969, so 182 days had elapsed before the Zodiac Killer's third confirmed cryptogram arrived at the San Francisco Chronicle on April 21st 1970.

Paul Avery wrote on April 22nd 1970, in an article entitled Zodiac Sends New Letter-Claims Ten, that "the killer who calls himself Zodiac has once again written to the Chronicle. In a letter received yesterday, Zodiac claims he has killed again". This letter was received by the San Francisco Chronicle on April 21st 1970, the exact day and month the letter from Stonington, Connecticut was postmarked from the anonymous sender to Edgar Allan Poe. This all may have been coincidence, but it would certainly be worth looking for the Zodiac Killer's initials as part of the answer to the 13-Symbol cipher.

That answer could be "This is the Zodiac speaking. By the way have you cracked the last cipher I sent you? My name is Fk, I'm crackproof", given to us in the Zodiac Killer's postcard five-and-a-half months later as a big hint to its decipherment. The 340 character cipher was split into rows of 9, 9 and 2 sections. The 13-Symbol cipher may have been split into 2. 2 and 9 sections, with the circled 8's beginning each section of the phrase. The letters K and M were already in place for a perfectly circular message, as highlighted in the October 5th 1970 communication by the Zodiac Killer, in which he supplied us with the phrase Fk I'm crackproof.