We know the Zodiac Killer was an avid reader of the newspapers, often replying to law enforcement officers such as Vallejo Police Chief Jack E. Stiltz and Captain Martin Lee, as well as arbitrary content from the newspaper articles themselves. Therefore, would it be any great surprise if he found his pseudonym in the newspapers as well. Covered very briefly on Zodiac Killer Mystery forum and Tom Voigt's old message board, this finding deserved another showing. The Zodiac Killer and the influence of astrology has been widely covered throughout the years, but below we have a column that featured daily over several decades in many newspapers, including the Vallejo Times-Herald throughout the relevant time period of the Lake Herman Road and Blue Rock Springs attacks. The Star Gazer astrology column was created by Clay R. Pollan and ran in over 400 newspapers. He was a newspaper editor and publisher for many years, and founded the Inter-American Features Syndicate in the mid 1940s which distributed Star Gazer and Scram-lets puzzles.

The columns began with "To develop the message for (day), read words corresponding to numbers of your Zodiac birth sign". We mention the Zodiac Killer crosshairs being found in conjunction with the word "Zodiac" on a watch, but here we have a column that would have featured in the Vallejo Times-Herald in 1969, that contained a hidden message within the Zodiac horoscope - and on July 31st 1969, the Zodiac Killer mailed a hidden message in three portions of code, one of which was sent to the Vallejo Times-Herald, and one which was mailed to the San Francisco Chronicle, in which he wrote "In this cipher is my idenity". Is it conceivable that the inspiration for his pseudonym was derived from this Zodiac horoscope, which further inspired him to begin his letter writing campaign with a concealed message?  

Twenty-one years later, could the Zodiac Killer have returned and used the very same technique, when he mailed the Celebrity Cypher. Luis Campos, born in Santiago, Dominican Republic is an inventor, poet and cryptographer who created puzzles and ciphers for the United Features Syndicate of New York, beginning in 1983. He would create six celebrity ciphers a week, featuring famous quotes from well-known people, past and present. The reader had to identify the person and quote from the encoded text. The characters in the cryptograms were deliberately spaced into separate words, as shown below.  

On September 25th 1990, somebody mailed the Celebrity Cypher to the Vallejo Times-Herald, approximately three months before the 1990 'Eureka' card - often associated with the Zodiac Killer. Bearing in mind the 408 cipher mailed to the San Francisco Chronicle, San Francisco Examiner and Vallejo Times-Herald on July 31st 1969, many have pondered whether this postcard was mailed by the Bay Area murderer.

We may now have two sets of Zodiac communications inspired by the hidden messages of Clay R. Pollan and Luis Campos, with the Vallejo Times-Herald the common denominator in both instances. We know the Zodiac Killer derived inspiration from the newspapers, but did this inspiration extend to mimicking the art of hidden messaging? This concept could have extended even further, when the Zodiac Killer designed his infamous unsolved 340 cipher, that may have been taken straight from the Dick Tracy comic and breakfast cereals of children - again receiving widespread publicity in the newspapers. See the Dick Tracy 340 Cipher article. 

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

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

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

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

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

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

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

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

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

David Oranchak, owner of the Zodiac Killer Ciphers website, gave a very interesting and informative presentation on the Zodiac ciphers at the Cryptologic History Symposium on October 22nd 2015. If you want to discover some of the features and quirks regarding the composition of the ciphers, this is an extremely good place to start. But there was one particular section that peaked my interest, despite the fact it would probably contradict a number of articles I have featured on this site. Nevertheless, I would like to present the part of the Cryptologic History Symposium here, using the words of David Oranchak. In the video, beginning at 34:37, David states "Here's an interesting coincidence. If you take two standard sized pieces of paper, 8 1/2 inches wide by 11 inches in length and you divide the paper into equal half inch squares, you end up with these sheets that have 17 columns and 22 rows. If you write both ciphers (the 340 and 408) back to back, you end up filling both sheets exactly with no leftover squares. It is an interesting coincidence. Does it mean that Zodiac drafted both of his ciphers together on two sheets of paper? It's an interesting question".

It certainly is an interesting question, bearing in mind the difficulty experienced in solving the 50-year-old 340 cipher and the still unsolved 18 characters at the foot of the 408 cipher. The Zodiac Killer stated in the 408 cipher, preceding the final 18 characters, that "I will not give you my name because you will try to slow down or stop my collecting of slaves for my afterlife". If the unsolved section of the 408 cipher didn't contain his name or identity, is it possible these 18 characters were supposed to bleed into the message on the 340 cipher. This has to a realistic proposition when we consider the 340 cipher begins with the final three letters of the word cipher. Was this just another coincidence - or did each cryptogram share half of the word cipher, as well as sharing a message? It is a compelling argument that the Zodiac Killer may have intended to leave only 12 unsolved characters at the foot of the first cipher (possibly decoding to "I am the Zodiac"), but the accidental omission of the word people from the message may have resulted in an unwanted extra 6 characters, thereby forcing a change of plan. Could the 18 characters now form part of a 21 character bridge (or more) between cipher one and two? The 408 cipher ending with cip and joining the her of the yet to be released 340 cipher. If the remainder of the 408 cipher and beginning of the 340 cipher was somehow conveying the idea of "sorry no cipher", in similar fashion to the October 27th 1970 'Halloween' card, then the message on the November 8th 1969 greeting card stating "I thought you would need a good laugh before you hear the bad news", may be pertinent to the cipher that accompanied it.           

Sorry no cipher written on the Halloween card once would have sufficed, to inform us that no code was present on the greeting card, yet the Zodiac Killer appeared to fashion it to mimic the Paradice and Slaves configuration on the card, which equally mimicked the possibility shown present in the 340 cipher on the right. This configuration perfectly bisected the 340 cipher (17 by 17) both horizontally and vertically.

By extension, from the Halloween card to the 340 cipher, was the Zodiac Killer telling us that the second cryptogram was "sorry no cipher"? And by extension, was the Zodiac Killer telling us exactly the same thing from the 408 cipher to the 340 cipher, hence the tantalizing her at the beginning of the cryptogram. It could be argued that the placement of her at the beginning and the near-Zodiac towards the end, is a little too convenient. A message of "sorry no cipher" through three sets of communications may be a bit difficult to shake off as coincidental.

If the Zodiac Killer created a rambling message akin to the 408 cipher and randomly allotted his cipher key, then he was extremely unfortunate to have crafted the possibility of the configuration on the right, involving the words paradice and slaves, by in each quadrant, with her at the beginning and Zodaik near the end. This is not what you want to achieve when you are trying to convince the world it's a genuine cipher, because people like me come along. The prospect of finding the same mini-message shared between the 408 and 340 cipher, that was found on the envelope inner of the Halloween card would certainly be "bad news" for some.

I would like to thank David Oranchak for his contribution regarding the Cryptologic History Symposium, and would encourage everybody who is interested in ciphers to click the highlighted link. Below is just one rudimentary example I have drummed together, using a screenshot of the Youtube video, keeping 7 of the 21 characters in their original format.

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

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

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

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

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

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

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

The Bay Area murderer mailed three communications in total to the San Francisco Chronicle, San Francisco Examiner and Vallejo Times-Herald on July 31st 1969, demanding that his ciphers be printed on the front page of the respective newspapers by Friday afternoon (August 1st). This is what he wrote to each newspaper after stating several facts about his crimes.

Vallejo Times-Herald - Here is a cyipher or that is part of one. the other 2 parts have been mailed to the S.F. Examiner + the S.F. Chronicle I want you to print this cipher on your frunt page by Fry Afternoon Aug 1-69, If you do not do this I will go on a kill ram page Fry night that will last the whole week end. I will cruse around and pick of all stray people or coupples that are alone then move on to kill some more untill I have killed over a dozen people.

San Francisco Examiner - Here is a cipher or that is part of one. The other 2 parts are being mailed to the Vallejo Times + S.F. Chronicle 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. This will last the whole weekend, I will cruse around killing people who are alone at night untill Sun Night or un till I kill a dozen people.

San Francisco Chronicle - Here is part of a cipher the other 2 parts of this cipher are being mailed to the editors of the Vallejo Times and SF Examiner. I want you to print this cipher on the frunt page of your paper. In this cipher is my idenity. If you do not print this cipher by the afternoon of Fry.1st of Aug 69, I will go on a kill ram-Page Fry. night. I will cruse around all weekend killing lone people in the night then move on to kill again, until I end up with a dozen people over the weekend. 

In a previous article we examined the present and past tense usage in the three letters, along with the stamps applied to the envelope, to make the case for the Zodiac Killer being a Vallejo resident. The following will be nothing groundbreaking, but examines the phrases and grammar used by the author to paint a picture of the subject when considering his identity. The Zodiac Killer threatened chaos over the weekend if his codes were not published on the front page of the papers. Unfortunately for him, the main two publications refused to bow to his threats. On August 2nd 1969, the San Francisco Chronicle under the title Coded Clue in Murders placed one-third of his cipher on page 4, while the San Francisco Examiner under the banner Vallejo Mass Murder Threat Fails (despite publishing the entire cipher) relegated it to page 9 on August 3rd 1969. This lowly showing in the San Francisco Examiner clearly upset the Zodiac Killer the most, when he hurriedly delivered by hand the August 4th 1969 'Debut of Zodiac' letter to the Examiner, stating "I was not happy to see that I did not get front page coverage". Putting aside the December 16th 1969 'Fairfield' letter (which many dispute), he never wrote to the San Francisco Examiner again.  

In a recent article we discussed the topic of geographic profiling to narrow the search field for an offender's home residence. Equally, the wording used by the Zodiac Killer in his communications may also help pinpoint a location, or at the very least give us an insight into his comfort zone or movements. Target or Victim Backcloth is the model by which a murderer may select his victims. The Zodiac Killer (wherever he lived) would have selected his victims dependent upon availability and location, along with the constraints of time and the day of the week. For a serial killer committing his crimes in Vallejo, his knowledge of the Target Backcloth may govern the types of individual he chooses. This seemed evident in his choice of couples parked up in lonely areas on December 20th and July 4th.

His communications to the San Francisco Chronicle, San Francisco Examiner and Vallejo Times-Herald exemplified this knowledge of a Target Backcloth perfectly, when he only threatened to kill couples in his address to the Vallejo Times-Herald (or stray people). He knew exactly where to find them, despite the fact it was highly unlikely he would continue to kill in the same area again. The Zodiac Killer never used the word couples in his address to the San Francisco Chronicle and Examiner, suggesting that his knowledge of the Target Backcloth was less comprehensive and more uncertain in this city- and why at San Francisco he would target a lone taxicab driver rather than target the location, as he did at Lake Herman Road and Blue Rock Springs. As Kim Rossmo stated  "The San Francisco murder differs significantly from the Zodiac's other crimes. Up to this point he was hunting in locations that had a good probability of containing his desired victims. Target selection was a function of area, not of an individual. However, it is unlikely the Zodiac was successful in all his searches; serial killers typically engage in extensive hunting activities, and for every attack there are many unsuccessful search attempts. In San Francisco, however, the Zodiac controlled the situation through his selection of victim type. The need for such control could be indicative of the distance the Zodiac had to travel to the crime site. Criminals who travel longer distances to offend are less likely to use uncertain target selection techniques".  

The Zodiac Killer wrote of ​"killing lone people in the night" or "killing people who are alone at night" to the Chronicle and Examiner, which is exactly what he did just over two months later on October 11th 1969, when Paul Stine was brutally gunned down inside his taxicab at Presidio Heights. The target selection began with the individual not the location. He then directed Paul Stine to an area to facilitate his best chance of escape. A Target Backcloth requires knowledge of an area and will govern to some extent the victims chosen, as displayed by some serial killers who target sex workers.   

It was considered that if the Zodiac Killer lived in Vallejo, he likely had a 9-5, Monday to Friday profession, based upon the fact, that when constrained by time he murdered close to home on a Friday, but unconstrained (on his day off), he was able to venture further afield to San Francisco and Lake Berryessa. He admitted as much in all the July 31st 1969 communications.

"I will go on a kill ram-Page Fry. night. I will cruse around all weekend" and "I will cruse around killing people who are alone at night untill Sun Night". The Zodiac Killer may potentially be limited in searching for courting couples on weekdays, but certainly not for lone victims in San Francisco, Vallejo or elsewhere Yet he has specifically tied himself to murder within the parameters of Friday night to Sunday night in these letters, and therefore highly suggestive he is employed on a weekday basis. 

The Brentingham model of geographic profiling details an activity space where an individual lives, works and plays. The Zodiac Killer targeted the San Francisco Chronicle, San Francisco Examiner and Vallejo Times-Herald in his first communications to the newspapers, indicating that Vallejo and San Francisco were his primary sites of travel. He most likely lived and worked in both. The newspapers he chose and the location he lived, part of his mental map, exhibited to its fullest extent when he subconsciously used the present and past tense in his three July 31st 1969 letters 

The Zodiac Killer - A Vallejo Resident [Part 2]​   

The 408 cipher, mailed in three parts to the San Francisco Chronicle, San Francisco Examiner and Vallejo Times-Herald on July 31st 1969 had 18 unsolved characters at its foot. However, the Zodiac Killer likely made an error when transferring his original message into the encrypted version, accidentally omitting the word "people" from the section of code mailed to the San Francisco Chronicle: "The best part of it is that when I die I will be reborn in paradice and all the (people) I have killed will become my slaves". Had he transferred the message correctly, the intended version would have had only 12 unsolved characters in which his identity may have resided, such as "I am the Zodiac". After all, he promised us his identity not his name. What are the chances the Zodiac Killer left a similar message at the foot of the 340 cipher?

Professor D.C.B. Marsh, in the October 22nd 1969 San Francisco Examiner newspaper article by Will Stevens, laid down a challenge to the Zodiac Killer to reveal his name. The newspaper stated "Dr Marsh told the Examiner today: "The killer wouldn't dare, as he claimed in letters to the newspapers, to reveal his name in the cipher to established cryptogram experts. He knows, to quote Edgar Allen Poe, that any cipher created by man can be solved by man. Zodiac has not told the truth in his cipher messages to the Examiner, the Chronicle and the Vallejo Times-Herald. Zodiac has not done this, because to tell the complete truth in relation to his name -in cipher code - would lead to his capture. I invite Zodiac to send The American Cryptogram Association a cipher code - however complicated - which will truly and honestly include his name". It was speculated that the Zodiac Killer certainly wasn't going to provide another conventional cryptogram to be easily decoded, so instead created the appearance of a cryptogram with hidden "puzzles" contained within it, such as "paradice" and "slaves" running vertically and horizontally across its mid-section. This was later revealed in the 'Halloween' card, where the Zodiac Killer belatedly informed us the 340 code was "sorry no cipher" and placed "paradice" and "slaves" in a cross formation to point us in the right direction.   

The "sorry no cipher" section of the 'Halloween' card has one section running from bottom to top. The '13 Hole' postcard mailed before this offering has "Fk I'm crackproof" flipped upside down. This gave rise to the idea that the 340 cipher needed to flipped vertically, which I was able to do on Dave Oranchak's excellent Webtoy on the Zodiac Killer Ciphers website. 

​When Professor D.C.B. Marsh laid down the challenge to Zodiac, it was initially considered that the message at the foot of the 340 cipher may have teased the American Cryptogram Association with something like "next time I will tell you who the Zodiac is", bearing in mind where the near-pseudonym was placed. Then, five months later he would follow this up with the reveal of his name, which he effectively teased us with by stating "This is the Zodiac speaking. By the way have you cracked the last cipher I sent you. My name is...."  

This statement is very telling, when we consider that it was patently obvious that his last cipher hadn't been solved - so why did he add this to the opening of the April 20th 1970 communication? The final section of the 340 cipher may explain why he began this correspondence in the way he did. It may be conceivable that the last section of the 340 cipher promised to reveal his name in the next cipher, hence the blatantly obvious introduction in the April 20th 1970 communication, of "This is the Zodiac speaking. By the way have you cracked the last cipher I sent you. My name is...."  We effectively have to bridge the gap between "I am the Zodiac" (if correct) on the 408 cipher to "My name is" on the April 20th letter. The obvious connector would be the promise of a new cipher or code containing the Zodiac Killer's name. 

It is notable that the 340 cipher begins with "her" (the last three letters of cipher), however, it is impossible to form the word "cipher" in the format offered. The uniform 17 X 20 pattern of the cipher would be broken by adding "cip" to the beginning. For this section to provide us with the word "cipher" within the existing pattern and the promise of a new cipher containing the Zodiac's name, the 340 cipher has to be flipped - possibly as the 'Halloween' card and '13 Hole' postcard had hinted nearly a year later. Other than the 408 cipher mailings, every other Zodiac correspondence began with the introduction of "This is the Zodiac Speaking". The 340 cipher, when flipped, enables this introduction to begin the 340 character message also. ​ 

But what is the likely message encoded at the foot of the cipher? Without having decoded it, I can only make a calculated guess from other Zodiac correspondence. In the August 4th 1969 'Debut of Zodiac' letter, the killer wrote "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".  

In the April 20th 1970 communication, the killer wrote "By the way have you cracked the last cipher I sent you. My name is...." 

Therefore, I will use the literal words of the Zodiac Killer to complete the last 27 characters of the 340 cipher, obviously changing "last" to "next".
​
By flipping the 340 cipher vertically we are able to use the clue of "Zodiac" to generate his usual introduction and then form the bridge between cipher one and cipher three with the promise of his name in cipher two, using the words of the Zodiac Killer himself. Whether this analysis has any semblance of truth is another matter entirely. 

It is no coincidence that the Zodiac Killer only wrote "in this cipher is my idenity" in the letter he mailed to the San Francisco Chronicle on July 31st 1969, because this one-third of the cipher contained the 18 unsolved characters at its foot. This was also the only letter of the three to begin with "This is the murderer". The other two communications to the San Francisco Examiner and Vallejo Times-Herald began with "I am the killer". This shift in introduction may be completely accidental, may be subconscious or may be completely deliberate on account of the "identity" he is to place at the foot of the cipher. The author of these three communications had deliberately separated them into three parts, and therefore when he was preparing the San Francisco Chronicle letter, one would like to think he was considering the opening line when placing his identity at the end of the cipher. If he was ever going to disclose his identity (but not his name), then logically it would be an extension of "I am the killer" to "I am the Zodiac Killer", and therefore satisfy the quota of 18 unsolved characters required by the cipher. I have inserted "I am the Zodiac Killer" at the end of the opening lines of the San Francisco Chronicle and San Francisco Examiner to show how the revelation of his identity in the Chronicle better suits the introduction of "This is the murderer". 
San Francisco Chronicle: "Dear Editor, This is the murderer of the 2 teenagers last Christmass at Lake Herman + the girl on the 4th of July near the golf course in Vallejo. I am the Zodiac Killer" 
San Francisco Examiner: Dear Editor, I am the killer of the 2 teen-agers last Christmass at Lake Herman and the Girl last 4th of July. I am the Zodiac Killer"     

The Zodiac Killer may have accidentally dropped the word "people" from the San Francisco Chronicle cipher (shown in red above) when he transitioned from one cipher to another, unwittingly missing out this word from his original draft to final version, and thereby forcing him to switch from the intended 12 characters he meant to leave, to a revised 18 characters.To rectify his mistake he simply changed "I am the Zodiac" to "I am the Zodiac Killer". The confirmed murderer of five never used the term "Zodiac Killer" in any of his subsequent communications, opting for "This is the Zodiac speaking", but may have had his hand forced on this occasion. It would have been relatively easy to just rewrite the San Francisco Chronicle cipher, but this was an easy solution. One can see how the Zodiac Killer chose his words in the October 13th 1969 letter, opening up with "This is the Zodiac speaking. I am the murderer of the taxi driver over by Washington St + Maple St last night". He uses the words "I am" because he has already introduced himself as the Zodiac. In the July 31st 1969 San Francisco Chronicle letter he uses the words "This is the murderer" because he has thus far failed to introduce himself, which he reserves for the final line of the cipher, stating "I am the Zodiac (Killer)". It is effectively a reversal of the Paul Stine letter. 
Paul Stine letter: "This is the Zodiac speaking. I am the murderer of the taxi driver".  
San Francisco Chronicle: "This is the murderer of the 2 teenagers. I am the Zodiac Killer"    

The murderer would very quickly introduce himself in the August 4th 1969 'Debut of Zodiac' letter: "This is the Zodiac speaking. In answer to your asking for more details about the good times I have had in Vallejo, I shall be very happy to supply even more material. 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". He was introducing himself as "Zodiac", so when the police did eventually crack the code, in effect, they would have "had Zodiac". 

An anonymous caller in San Francisco declared that whoever devised the code "would have to have a vast knowledge in three fields - surveying, nautical science and marksmanship". How the caller could derive that the triple murderer had a vast knowledge of marksmanship from these attacks is hard to justify, not to mention nautical science and surveying. Was the Zodiac Killer ringing the police and blowing his own trumpet? The murderer did ultimately commit his murders with varied weaponry and did eventually introduce a map and radians into his communications.   

If we are looking for an identity or pseudonym in the 18 unsolved characters of the 408 cipher, then it must include appropriate word usage in order to increase the originally intended 12 characters up to 18 characters. So if the original message was "I am the Zodiac" or "Zodiac Killer", then the author had to supplement it with an extra 6 characters to replace the word "people". The simplest avenue available was to add "Killer" or "I am the", in order to generate these 6 characters. These were all used consecutively in two of the three communications mailed on July 31st 1969, when the Zodiac Killer wrote "I am the killer of the 2 teenagers last Christmass at Lake Herman + the girl last 4th of July" to the San Francisco Examiner and Vallejo Times-Herald.  

The Zodiac Killer had seemingly failed to fully convince Vallejo Police Chief Jack E Stiltz, who was less than satisfied that the letter writer and killer were one and the same, urging the author of the July 31st 1969 letters to send in more details of the crimes. The Zodiac Killer immediately dispatched the 'Debut of Zodiac' letter on August 4th 1969 with the introduction of "This is the Zodiac speaking". Although the Zodiac Killer could add more details of the crimes in this new letter to prove he was the killer, It is conceivable he revealed his pseudonym after only four days to inextricably link himself to the first three letters. The only way he could achieve this beyond any doubt, was to reveal a significant word in the unsolved cipher. Then the police would know for certain when the code was broken, that the author of the August 4th 1969 letter was not only the killer, but the designer of the cryptogram. So he introduced his pseudonym "Zodiac" earlier than he had originally intended and immediately rushed it off to the San Francisco Examiner newspaper on August 4th 1969, before the cryptogram was solved.

​Remember, if Vallejo Police Chief Jack E. Stiltz had not urged the author of the July 31st 1969 letters to send in more details to prove the letter writer was the killer, the 'Debut of Zodiac' letter would likely never have been written and sent to the Examiner. The "Zodiac" would still have been the "killer" by the time of the Paul Stine murder. He revealed his pseudonym to link himself to the San Francisco Chronicle's 18 characters, but unfortunately for him, he clearly underestimated the difficulty of the encryption. The release of his identity or pseudonym "Zodiac" so quickly, may lend credence to its presence in the remainder of the 408 cipher, and by extension, the 18 unsolved characters harboring a genuine and coherent message. 

​"This is the Zodiac speaking. 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 18 UNSOLVED CHARACTERS [PT1]
THE 18 UNSOLVED CHARACTERS [PT2]
​THE 18 UNSOLVED CHARACTERS [PT3]

Many attempts have been made to conclusively link the Riverside murder of Cheri Jo Bates on October 30th 1966, along with the accompanying communications, to the Zodiac Killer. The three 'Bates' letters, on April 30th 1967, ended the Riverside chapter, with the three July 31st 1969 letters to the San Francisco Chronicle, San Francisco Examiner and Vallejo Times-Herald, beginning the Zodiac chapter. But is the hidden identity contained within the 408 cipher (if it exists) somehow connected to the hidden author of the November 29th 1966 'Confession' letter? It is paramount to make a distinction between name and identity when attempting to formulate any cohesive link between the Confession letter and 408 cipher, because the Zodiac Killer claimed he wouldn't give us his name in the decoded 408 cipher, but did claim it would reveal his identity.

​When we take a close look at the decoded 408 cipher, it can be argued that he made a fundamental error when he encoded his original message, accidentally omitting the word "people" in the ciphertext. This is explained in 'The 18 Unsolved Characters [Pt3]'  This effectively created a shortfall of 6 characters in his 408 cipher, which had he not done, would only have left 12 unsolved characters at the end of the message. In view of the Bay Area murderer identifying himself as "Zodiac" just four days later, it was considered that his impatience may have compelled him to reveal his identity earlier than he would have liked, and "Zodiac" was integral to his identity in the 12 characters at the end of the 408 cipher. The hidden identity, therefore, the "Zodiac Killer". 

Had the 408 cipher read "the best part of it, is that when I die I will be reborn in paradice and all the people I have killed will become my slaves", and the last 12 characters contained his identity, then by extension, we should be looking backwards to Riverside for the previous time he used a form of cryptic or hidden message. The only letter that contained such an instance, was the November 29th 1966 letter beginning "The Confession by - - - - - - - - - - - -".  This contained 12 underscores of, presumably, the hidden name or identity of the killer. For those believing a connection from Riverside to the Bay Area, the potential murderer of Cheri Jo Bates may have cloaked his identity behind 12 underscores in the Riverside 'Confession' letter and 12 characters in his communication with the San Francisco Chronicle on July 31st 1969.  The 'Bates' letters correlated via a trinity of letters, whereby the 'Confession' letter correlated through the identity of twelve.

This analysis fundamentally fails to successfully bridge the divide from Riverside to the Bay Area, as many arguments have before - and the connection between the murder of Cheri Jo Bates and associated communications, to the Zodiac Killer, will remain a hot button topic for many years to come no doubt - but the search goes on.

In the last three articles it was proposed that the author of the 408 cipher may have left his identity within the final 18 characters. He specifically told us that he would not give us his name, but assured us his identity was concealed within the cipher - reasoned to be something like "I am the Zodiac Killer." The theme of his identity and name were integral to the final third of the cipher and letter mailed to the San Francisco Chronicle on July 31st 1969, and may very well have manifested through both his second and third ciphers as well. The third cipher began with "This is the Zodiac speaking. By the way have you cracked the last cipher I sent you. My name is...."- therefore, the final line of the second cipher (340 cipher) may be the 'narrative bridge' between the first and third cryptic offerings. 

The first cipher achieved everything the Zodiac Killer had wished for. He had fashioned using threats and newspaper rivalry maximum exposure for his handiwork, which was very quickly published by the Vallejo Times-Herald, San Francisco Examiner and San Francisco Chronicle. The failure of Zodiac to give us his name did not satiate the desire of some in the quest for the real identity of the killer, and was championed by Dr D.C.B. Marsh, president of the American Cryptogram Association, who on October 22nd 1969 in an article published by the San Francisco Examiner, stated "The killer wouldn't dare, as he claimed in letters to the newspapers, to reveal his name in a cipher to established cryptogram experts. "Zodiac" had not done this, Marsh suggested, because to tell the complete truth in relation to his name, in cipher code, would lead to his capture. I invite 'Zodiac' to send The American Cryptogram Association a cipher code-however complicated."

​This article was not to go unnoticed by the killer, who, two and a half weeks later mailed his infamous 340 cipher, unsolved to this day according to official sources. This cipher was to become the all-important bridge between cipher one and three. If he gave us his identity (the Zodiac Killer) in the unsolved 18 characters of cipher one, and stated "my name is" in cipher three (supposedly giving us his name), then by logical extension, cipher two should have been the promise of a name, and the conduit between the two.

If we can provide a compelling reason to show that the near-Zodiac on the final line of the 340 cipher was actually intended to be deciphered to 'Zodiac', then we are left with the final two characters of the cipher to decode, thereby bridging the gap between cipher two and three. 
Using the most powerful supercomputers in the world and the talent of some of the brightest minds in cryptography, the 340 cipher has failed to buckle. So, it's time to use the character of the Zodiac against himself, and his willingness to respond to the newspapers.

If the Zodiac Killer is responding to Dr D.C.B. Marsh, then he clearly isn't prepared to give us his name immediately in the November 8th 1969 '340 cipher', as the opening line in his April 20th 1970 communication would testify to. It would be over five months later that he stated "my name is".  Therefore, the final two characters of the 340 cipher are the conclusion to an open-ended promise of something more to come, in similar fashion to "my name is."  The Zodiac Killer certainly wasn't going to miss the opportunity to keep Dr D.C.B. Marsh and the public waiting just a little bit longer. 
​
The final line or sequence of the 340 cipher probably read "The next cipher will reveal who the Zodiac is" or "I will soon reveal who the Zodiac is" - or something along these lines. This 'promise' can be seen in his opening gambit of the April 20th 1970 communication: "This is the Zodiac speaking. By the way have you cracked the last cipher I sent you. My name is...." ​
The statement of "by the way have you cracked the last cipher I sent you" is superfluous, as he knows only too well the 340 cipher has not been cracked, yet, it also lacks his usual abrasive sarcasm. However, it is followed by "my name is", and therefore could be construed as the conclusion to his promise from the final line of his 340 cipher and to Dr D.C.B. Marsh, and the allegorical  bridge between the two ciphers.

But how do we know that the near-Zodiac on the final line of the 340 cipher was to be decoded to 'Zodiac'?  Because he fashioned a bridge between cipher two and three using his pseudonym. Placing the real spelling of Zodiac under the '340 cipher' version of Zodiac, and counting the alphabetical difference numerically between the columns (see here), we achieve the numbers 000888. When combined, the three circled 8's found on the '13 Symbol' cipher.
​
These six characters of the 340 cipher were effectively carried forward numerically and placed front and center of the '13 Symbol' cipher design. You will also notice that the two characters either side of three 8's (shown on the right), are both visible either side of the near-Zodiac on the 340 cipher. A total of eight characters and three circled 8's the common link or bridge between cipher two and three - in which the name of Zodiac played a pivotal part in the formation of the 'My Name is Cipher'. The story is now complete. 

The Zodiac Killer stated on July 31st 1969 "I will not give you my name, but in this cipher is my identity." He promised in the 340 cipher, in a response to Dr D.C.B. Marsh, that he would soon reveal his name. Then, five and a half months later, on April 20th 1970 he stated "This is the Zodiac speaking. By the way have you cracked the last cipher I sent you. My name is...." 

Do ciphers two and three really contain a full and coherent message, not dissimilar to the 408 cipher solution, or had the Zodiac Killer taken Dr D.C.B. Marsh's advice "to send The American Cryptogram Association a cipher code - however complicated", and taken it a step too far?

This is the final installment covering the 18 unsolved characters at the foot of the 408 cipher. Part one. Part two.
Nobody knows for sure the exact process in which the Zodiac Killer crafted the three ciphers mailed to the San Francisco Chronicle, San Francisco Examiner and Vallejo Times-Herald, but one possibility is that the author wrote the message first and then transferred it to the chosen grid formation, with the intention of leaving a number of spaces to insert his identity at the end of the cipher - a signature of sorts. The killer actually stated this: "I want you to print this cipher on the front page of your paper. In this cipher is my idenity."

We now know his identity as the 'Zodiac Killer', so one may expect to see 12 unsolved characters remaining at the foot of the cipher. He could have signed off the cipher with the wording 'Zodiac Killer' or 'I am the Zodiac', but either way, he would have had to leave himself 12 available spaces to complete the entire grid of 24 rows and 17 columns. The reason for believing he intended to leave 12 characters for his identity, rather than 18, is that he transferred the message from draft to grid incorrectly, actually omitting one important word - people.
​
The author had just switched from cipher 2 to cipher 3 (see below), which may have instigated the error.
​
In the trinity of letters to the newspapers, the Zodiac Killer described the inevitable consequences of not printing his ciphers. 
To the Vallejo Times-Herald, he wrote "I will cruse around and pick of all stray people or coupples that are alone then move on to kill some more untill I have killed over a dozen people."
To the San Francisco Examiner, he wrote "If you do not print this cipher, I will go on a kill rampage Fry night. This will last the whole weekend, I will cruse around killing people who are alone at night untill Sun Night or untill I kill a dozen people." 
To the San Francisco Chronicle, he wrote "I will cruse around all weekend killing lone people in the night then move on to kill again, until I end up with a dozen people over the weekend."  

With regards to his threats, he used the word "people" no less than six times, so it was probably unfortunate that this was the word he mistakenly dropped from his grid when transferring the message to it.
The murderer wrote in the cipher "the best part of it, is that when I die I will be reborn in paradice and all the I have killed will become my slaves." It is highly likely that he accidentally reproduced his message incorrectly and failed to include the word "people" in the resultant cipher. The cipher should have read "the best part of it, is that when I die I will be reborn in paradice and all the people I have killed will become my slaves."

Since "killing", "kill" and "people" were routinely written 'hand in glove' in all the three newspaper communications, then it is no great leap of faith that the two words should have been bound together in the cipher as well. 
In the San Francisco Chronicle portion of the cipher below, I have added "people" into the grid, thereby shifting the cipher across six spaces. The resulting cipher now contains 396 characters of legible text, leaving only 12 unsolved characters at its foot. The 12 characters we discussed earlier, in which the author had reserved for his identity or pseudonym. Signing off with the 'Zodiac Killer' or 'I am the Zodiac'.

However, the Zodiac Killer had made an error, accidentally omitting the word "people", and consequently had to improvise by using a combination of 'Zodiac Killer' and 'I am the Zodiac' to enable full use of all 408 spaces on the 24 X 17 grid. He may have settled for 'I am the Zodiac Killer', thereby satisfying the 18 spaces he had inadvertently left himself.

The idea of a 396 letter message (including "people" within it) would have negated the possibility of creating 30 rows by 13 columns totaling 390 characters - which is why he didn't do it. Therefore, he opted for 17 by 24, creating the grid we have been accustomed to. 

What methodology he employed to encrypt these final 18 letters is another matter entirely.    

The blue square shows the end of the word "the". One can see that by moving the letter 'E' across two places to accommodate "those", the remainder of the cipher would be equally shifted. If we added "people" after "the", then the remainder of the cipher would be shifted six places across. The result of this would be removing the final 2 or 6 characters from the 408 cipher.

This strikes to the heart of whether the Zodiac Killer originally intended to leave a predetermined identity at the foot of the cipher. He ended up with 18 characters, which to this day remain unsolved. If he had intended to place "those" or "people" in the cipher, but transferred his message incorrectly, then the idea that 18 characters were purposely left to reveal his identity fails to materialize. His new identity would drop to 12 or 16 characters. The 4 consecutive character drop down, from the 8th to 24th line, would also not occur. 

In the last article I suggested that the final 18 characters could read "I am the Zodiac Killer", based on his wording in the trinity of July 31st 1969 communications. With the addition of "people" his intended message could have been relegated to the signature "Zodiac Killer" or "I am the Zodiac" ​ With the addition of "those", an altogether different message would likely have been created. His original intention may have been to create a 12 or 16 character message, but was forced to improvise into a longer version, created by the error on line 17. However, this would negate the premise of the previous article to some extent.
 
To presuppose an original 18 characters being left over for the designated purpose of his identity, would make the assumption that his original message read "The best part of it is that when I die I will be reborn in paradice and all the I have killed will become my slaves," and he transferred it to the cipher correctly.

The idea of a random filler to flesh out a cipher doesn't sit well, when we consider how easy it is to just slightly redesign the message to use all the 408 available spaces. This suggests the 18 unsolved characters do have meaning, and do contain the identity or pseudonym of the Zodiac Killer. This makes more sense than a real name, bearing in mind the author has already decided against this option on lines 18 and 19.

If the Zodiac Killer's original message was 392 or 396 letters in length, he could have created a completely different grid formation with reduced leftovers or none at all, such as 6 rows of 22 characters = 132, mailed to each of three newspapers. This would give us a total of 396. However, he chose to opt for 17 characters in each row, thereby leaving more unused characters. For this reason, there appears a purpose behind the notion of a killer leaving us his identity.
​
Since he hadn't revealed his pseudonym at this juncture, can we assume that part of the 18 unsolved characters held the words "Zodiac Killer." The precursor of "I am the"- the beginning of the 18 characters, just like the introduction written on the San Francisco Examiner and Vallejo Times-Herald newspapers.   

THE 18 UNSOLVED CHARACTERS [PT1]  
THE 18 UNSOLVED CHARACTERS [PT3]

In a previous article it was considered that the Zodiac Killer's identity was born on August 3rd 1969, but on this occasion I shall take an altogether different approach, and consider the possibility that the Bay Area murderer had already decided upon the pseudonym Zodiac when he mailed the trinity of letters and ciphers to the Vallejo Times-Herald, San Francisco Examiner and San Francisco Chronicle on July 31st 1969.
The San Francisco Chronicle letter (part 3) reads as follows "Here is part of a cipher the other 2 parts of this cipher are being mailed to the editors of the Vallejo Times and SF Examiner. I want you to print this cipher on the front page of your paper. In this cipher is my idenity. If you do not print this cipher by the afternoon of Fry.1st of Aug 69, I will go on a kill ram-Page Fry. night. I will cruse around all weekend killing lone people in the night then move on to kill again, until I end up with a dozen people over the weekend." The final 18 characters of the San Francisco Chronicle code remain undeciphered. However, the clues to breaking the remaining portion of the cipher may reside within the letters themselves. 
The 408 cipher message read "I like killing people because it is so much fun it is more fun than killing wild game in the forrest because man is the most dangerous animal of all to kill something gives me the most thrilling experence it is even better than getting your rocks off with a girl the best part of it is that when I die I will be reborn in paradice and all the (people) I have killed will become my slaves I will not give you my name because you will try to slow down or stop my collecting of slaves for my afterlife. ebeorietemethhpiti."  The unbroken characters are shown in red.     

The murderer chose his words carefully, stating "in this cipher is my identity" rather than his name. This became evident when the vast majority of the 408 cipher was cracked a matter of days later, and the killer revealed "I will not give you my name because you will try to slow down or stop my collecting of slaves for my afterlife." This still left open the possibility that his identity or pseudonym was contained in the 408 cipher. The San Francisco Chronicle letter was the only one of the trinity that contained "in this cipher is my identity," so logically, one could conclude that the 18 undeciphered characters at its foot, was the location of the murderer's identity.
If the killer had already decided upon his pseudonym when he wrote the three July 31st 1969 letters, then his decision to begin all three letters with "This is the murderer" and "I am the killer" (twice) was deliberately engineered to withhold the pseudonym Zodiac from the letters. The reason being - it was concealed in the final 18 characters of the 408 cipher.
It could be argued, that if he was to reveal his identity or pseudonym in the 408 cipher, then logically he would sign off the cryptogram with it. This was also apparent in the 340 cipher, with the near-Zodiac tantalizingly placed on the final line. 
If the Zodiac Killer had revealed his pseudonym straight away, then one of the letters would have opened with "This is the Zodiac" rather than "This is the murderer" (exactly like the August 4th 1969 letter). The other two letters would have opened with "I am the Zodiac Killer" rather than "I am the killer". But the murderer and author of the letters wanted to hide his pseudonym for now, and conceal it in the final 18 characters of the 408 cipher.    

We can now complete the 408 message:
"I like killing people because it is so much fun it is more fun than killing wild game in the forrest because man is the most dangerous animal of all to kill something gives me the most thrilling experence it is even better than getting your rocks off with a girl the best part of it is that when I die I will be reborn in paradice and all the (people) I have killed will become my slaves. I will not give you my name because you will try to slow down or stop my collecting of slaves for my afterlife. I am the Zodiac Killer."​
This is an attempt at reasoning a solution from within the letters themselves, and not a claim of a definitive solution 

THE 18 UNSOLVED CHARACTERS [PT2]
THE 18 UNSOLVED CHARACTERS [PT3]

It seemed rather fortunate that the 'Halloween' card mailed on October 27th 1970, if designed totally independently to the 340 cipher, that Paradice and Slaves could be found perfectly bisecting the 340 cipher, 17 by 17 characters. Not to mention the word "By" being found in all four quadrants. This is discussed in more detail in the article 'The Illusion of the 340 Cipher.'  
The 'Halloween' card was almost certainly highlighting the Lake Berryessa attack on Bryan Hartnell and Cecelia Shepard, tied up with rope (plastic clothesline) and brutally stabbed sixteen times by the Zodiac Killer. The phrase "peek-a-boo you are doomed" referencing the children's game peekaboo, where 'hiding behind that tree' is sometimes added. This would also be the second time "by knife" would be used - linking the 'Halloween' card to the Volkswagen Karmann Ghia of Bryan Hartnell.
Since these two 'methods of death' (rope and knife) were instrumental to the attack on the young couple, we will focus on Paradice, Slaves, By Knife and By Rope. 
On the 'Halloween' card it is apparent that "By" is written vertically for "knife" rather than horizontally, as displayed by the other 'methods of death'. Could this be a sinister inference to a knife being driven downwards and the predominant focus of this card?   

If we color in the five characters underneath the 'Y' in the bottom left quadrant of the cipher, as is portrayed on the 'Halloween' card, it can be seen that the 'right facing V' would represent the 'E' of knife.
If we  color in the four characters underneath the 'B' in the bottom right quadrant of the cipher, as is portrayed on the 'Halloween' card, it can be seen that the 'right facing V' would represent the 'E' of rope.
To complete the word Paradice and Slaves a 'left facing V' had to be found in the last section of both words for parity. In this instance a 'left facing V' represented the letter 'E'.
When the Zodiac Killer introduced his 408 cipher in the July 31st letters, he stated "Here is part of a cipher" or "Here is a cyipher." When challenged to design another cipher by D.C.B. Marsh in the San Francisco Examiner on October 22nd 1969, the 340 cipher arrived just over two weeks later. The article was entitled 'Cipher Expert Dares Zodiac to Tell Name'. Bearing in mind that the 340 cipher began with "Her," could it have started with "Here is a cipher" or "Here's a cipher" (to marry with the 'P' of Paradice) in direct response to cryptographic expert D.C.B. Marsh.
There are 10 'left or right facing' V's in the entire 340 cipher. If the latter hypothesis was correct, then at least 50% of these would be represented by the letter E, in respect of Here, Paradice, Slaves, Rope and Knife.  

We know the Zodiac Killer mailed his first three letters simultaneously on July 31st 1969, but what inspired him to design a trinity of cryptograms that when combined formed an almost complete and uniform message. It is likely he split the cipher into three parts for maximum newspaper coverage, however, we know little of what inspired him to design the codes in the first place.
The 'Zodiac Killer' pseudonym may never have existed had it not been for the skepticism of Vallejo Police Chief Jack E Stiltz, who insisted the three time murderer send more details to prove he was the 'cipher killer'. It was reasoned that something Zodiac read in the Sunday August 3rd 1969 San Francisco Examiner & Chronicle inspired him to repackage himself from "the murderer" to "the Zodiac". So, what drove the killer of David Faraday, Betty Lou Jensen and Darlene Ferrin to include a cryptogram alongside his deadly deeds and threats. The short answer is, nobody knows for sure- but we do know it took the Lake Herman Road double murderer just over seven months to finally begin his letter writing campaign. Was the killer always planning to kill again and write to the newspapers, or was it the extensive press coverage that inspired him to rise to the picture being painted of him. 
It seemed Detective Sergeant Leslie Lunblad beat a lone furrow in the pursuit of the murderer, but he was ably assisted throughout by many agencies, including the Criminal Investigation Bureau in Sacramento, Vallejo Police Department, Napa and Sanoma County sheriff's departments and Sergeant Jack Richard Oller, an investigator in the Fairfield office of the sheriff's department.  Jack Oller moved to Oakland, California in 1929 and served in the U.S. Army as a combat engineer in Europe. In 1978, he retired from the Solano County Sheriff Department with the rank of lieutenant.
Along with the Zodiac murder of Paul Stine on October 11th 1969 and the November 21st 1969 San Jose letter and cryptogram, we effectively had the entire shopping list of threats tabled in the 'Fairfield' letter, mailed on December 16th 1969. His threat of 'this state is in trouble..I will go for the Goverment life' may be traced back to a Sunday Times-Herald article on March 30th 1969, in which these law enforcement agencies were pivotal in the search for the Lake Herman Road murderer, including Sergeant Jack Oller. The Zodiac Killer's threat on police in the 'Fairfield' letter centered around Fairfield, Sacramento and Oakland. 
The inspiration behind the July 31st 1969 letters and cryptogram is difficult to ascertain, but often with the Zodiac Killer throughout it was something he read that triggered a response, such as the 'Debut of Zodiac' and 'Bus Bomb' letters.
The Sunday Times-Herald article on March 30th 1969 may or may not hold the answers, however, it was published four months prior to the July 31st trinity and did contain some noteworthy passages. Whether these were the trigger for the murderer to begin his letter writing campaign is pure speculation, but in the absence of alternatives it was worth considering.  
Here is the newspaper article in full:     

The youth, a scalor at Vallejo High, planned to make teaching his career. He was extremely active in Scouting, and was a member of the Interact Club at the high school.
"Last summer, he discovered girls" Mrs Faraday reminisced "but he hadn't done much dating- for one thing he could use the car only when I didn't need it to go to work." She is employed in the passenger reservations department at Travis Air Force Base. She said that when he did take the car for a date "he was good about observing curfews" (12.30 on Friday nights). "So I didn't think a thing about it that night. I was asleep when the phone rang at 3 am."
Mrs Faraday conversed with total composure, although the wounds haven't healed and won't. The same was true of the Jensens. Nothing in his 21 years as an army officer had prepared Lt Col. Verne Jensen for the shock of his younger daughter's death, however. He retired in 1963, decided to remain in Vallejo and now is employed as supply officer for the General Services Administration in San Francisco. The Jensens, with their elder daughter, Melodie, live at 123 Ridgewood Ct. " I don't feel vindictive" he mused "but I am apprehensive. I feel some nut is on the loose."
His words could have been uttered by Mrs Faraday, who said her principal concern that the killer be found was not based on vengeance but on her fears there may be further victims. "And, he'll find it easier the next time."
She said the other three Faraday children Debra, Robert and Steven "have handled the situation very well, I think. Presumably they have long and happy lives ahead of them, and they've got to live them."
The Jensens' lives remain clouded by the tragedy. "We'd like to have her back" Mrs Jensen said wistfully. "It took a lot to bring her this far."
At Hogan High Betty was an excellent student, a junior, she was hopeful of winning an art scholarship and she worked extremely well in several forms, some of which were displayed as I talked to the family. All three shook their heads negatively when asked if they had any ideas to the perpetrator. "We know he's a nut, but what kind of nut" Mrs Jensen replied. She added she was dubious about anything worthwhile could be gained in once again turning the spotlight on the murder case. "But we'll do anything we can to help" she declared.
As for the investigation's progress, Lublad said there has been considerably more than might be gleaned from news accounts of it. "If I talk to a suspect, I'll know positively whether he was there that night" he said cryptically. Beyond that, he would not comment. ​​

It is not difficult to cherry-pick certain phrases and words to fit ones agenda, however, we must consider that the murderer of David Faraday and Betty Lou Jensen likely read this article, and was buoyed by the description of his exploits as a "horrifying crime that may very well be the most celebrated murder mystery currently under investigation in California."
David Faraday's mother summed up her fears: "who said her principal concern was that the killer be found, not based on vengeance but on her fears there may be further victims. "And, he'll find it easier the next time."  
She wouldn't have to wait long for the killer to live up to her fears, promising he would "cruse around all weekend killing lone people in the night then move on to kill again, until I end up with a dozen people over the weekend."  
Detective Sergeant Les Lunblad's support may too have not gone unrecognized, with his assistance from a "score of law enforcement agencies in the state," including Sergeant Jack Richard Oller and the Fairfield Office.
If this newspaper article was the last major feature regarding the Lake Herman Road slayings, before the killer began his July 4th 1969 attack on Michael Mageau and Darlene Ferrin at Blue Rock Springs, then it is rather unusual that the ​Sunday Times-Herald article on March 30th 1969 would finish with the thoughts of Detective Sergeant Les Lunblad:in such a manner:
"If I talk to a suspect, I'll know positively whether he was there that night" he said cryptically.
Four months later, the murderer stated "I will not give you my name because you will try to slow down or stop my collecting of slaves for my afterlife," and he too said it cryptically.    

This is a combination of previous articles (with a little extra) under one banner, attempting to dispel the idea that the 340 code is a genuine cipher, and all attempts at trying to reveal a continuous and coherent message will ultimately fail. 
By overwhelmingly consensus, the 340 cipher will soon be entering its 50th year unbroken, remaining impervious to all attempts at releasing its secrets, despite innumerable attempts by the best codebreakers and codebreaking machinery thrown at it. Either the Zodiac Killer created a cipher so stunningly impossible and misjudged the complexity of his cipher, or he didn't create one at all. The '13 Symbol' and '32 Symbol' codes were simply too short, with too many variables to be broken by conventional means. The '32 Symbol' cipher has 29 unique characters, meaning you can literally fill in the blanks however you choose. The '13 Symbol' cipher is simply too short to be called a cipher, and any solution proffered can be readily dismissed without a valid key. The Zodiac certainly wasn't stupid and must have known this- pouring huge doubt on whether he ever intended them to be solved in a conventional manner. Therefore, why should we treat the 340 cipher any differently. The whole thing just appeared to be one big game for the Zodiac Killer, as we huffed and puffed long into the night trying to pry open his ultimate masterpiece.
Many observers have wondered whether the Zodiac Killer mailed the 'code key' to the Vallejo Police Department on August 10th 1969 under the guise of a "concerned citizen," unaware that it had already been solved by Donald Gene and Bettye June Harden, as well as the FBI in Washington. Unusual that he should then sit on the 340 cipher for many years to come, able to resist the temptation of revealing his subsequent ramblings. Keeping a secret for nearly 50 years would certainly take great restraint from a killer who bathed in the spotlight.
The 340 cipher may very well have been designed in the mind of the killer as early as August 4th 1969, or the moment his 408 cipher was cracked. The decrypted 408 read: "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 it is even better than getting your rocks off with a girl the best part of it is that when I die I will be reborn in paradice and all the (people) I have killed will become my slaves I will not give you my name because you will try to slow down or stop my collecting of slaves for my afterlife." 
The answer to the 340 cipher probably already lay within the text of the 408 cipher- just designed in an altogether different format. The clue would later reveal itself in the design of the 'Halloween' card, mailed on October 27th 1970, where the killer placed "Paradice" and "Slaves" in a cross formation, and told us "sorry no cipher." This wouldn't be the only time the Zodiac Killer gave us clues, alluding to the fact we were chasing a solution to a cipher that didn't exist.        

One of the best finds in recent years was by Tahoe27, a regular contributor to the Zodiac Killer Site forum, who discovered a connection between a Tim Holt comic and the 'Halloween' card. Many features on the cover of the comic parallel the 'Halloween' card, including the wording By Fire, By Gun, By Rope and By Knife, along with "Redmask" (the skeleton eyes) and "Lady Doom" (peek-a-boo you are doomed). However, I believe Tahoe27 is not convinced that the 'Halloween' card was authored by the Zodiac Killer. 
If the 'Halloween' card was authored by an impostor, who based the 'Halloween' card on the Tim Holt comic, then are we to believe he was extremely fortunate that a year earlier, the real Zodiac Killer just happened to create a 340 cipher containing the word "BY" in all four corners of the cipher, along with PARADICE and SLAVES being a possibility, running down and across the cipher on the midpoint vertically and horizontally, just like the configuration on the 'Halloween' card.
Admittedly, the words paradice and slaves have not been proven to exist in the 340 cipher, but the fact they are a distinct possibility by comparison to the 'Halloween' card appears another very fortunate stroke of luck- particularly if we believe the author of the 'Halloween' card wasn't the Zodiac Killer- and only considered the Tim Holt comic in his design of the 'Halloween' card. If the 'Halloween' card was crafted by the Zodiac Killer using only the Tim Holt comic, then the above still applies.
The more likely conclusion we could draw from this, is that the 340 cipher was designed with the Tim Holt comic in mind, and the 'Halloween' card (one year later) was giving us a clue.  

​On the right, we can see how the four words "BY" fit into each quadrant of the 340 cipher just like the 'Halloween' card offering. What are the odds that in each quadrant of 80 characters we would find the letters B and Y together either horizontally or vertically every time. Not to mention the fortunate appearance of paradice and slaves bisecting the cipher perfectly. The killer may even have given us his signature in the bottom right corner, along with the running total, which was seven and counting on November 8th 1969.
If this wasn't the intended design of the 340 cipher, then either the Zodiac Killer or an impostor got extremely lucky, in just happening upon a Tim Holt comic that mirrored the 340 cipher unintentionally. But we may just be able to prove a definite link between these two communications and confidently state that both were designed by the Zodiac Killer, and with a fair degree of confidence, argue that the 340 cipher is not a cipher in the true sense of the word. The majority of the characters likely filler, but in this instance, far more than the 18 characters at the foot of the 408 cipher. The reason we may be able to contend the 340 cipher is not a continuous and uniform message like the 408 cipher (and not a cipher as we believe one to be), is because the Zodiac Killer lined us up for a fall and then admitted to it a year later.
On the 'Dripping Pen' card accompanying the 340 cipher, the killer stated
"This is the Zodiac speaking. I though you would nead a good laugh before you hear the bad news. You won't get the news for a while yet. Could you print this new cipher in your frunt page? I get aufully lonely when I am ignored, so lonely I could do my Thing." Was that bad news to come on October 27th 1970, when he mailed the 'Halloween' card.
If we believe that the 'Halloween' card design is referring back to the 340 cipher, then the message concealed on the envelope inner of "sorry no cipher," is the Zodiac Killer finally admitting that the 340 cipher is not the real cipher we had thought.
He is declaring that the 340 is "no cipher," and is in fact, based upon the paradice and slaves configuration. This is why he crosses the phrase "sorry no cipher" to mimic the design of paradice and slaves, using 13 letters in both instances.
The Zodiac Killer could easily have written "sorry no cipher" just the once, but deliberately fashioned it to form a link between the 'Halloween' card design and the 340 cipher.
After searching for solutions to the 340 cipher for nearly half a century, the Zodiac Killer may have given us the answer to its design after just one year, but it was overlooked. We have took the phrase "sorry no cipher" as an apology, that he wasn't giving us a cipher in the 'Halloween' card, when in actual fact, he was apologizing for stringing us along for the best part of a year, and offered us the real solution to the 340 cipher on October 27th 1970, contained within the 'Halloween' card. You could say it was a "trick" and "treat" befitting of Halloween.

​You will notice that the paradice and slaves configuration from the 'Halloween' card fits nicely into the 340 cipher.
The two dashes on the 10th line are represented by the letter S. 
The left-facing V on the 9th column and 10th line are represented by the letter E. 
​The two addition signs on the 9th column are represented by the letter A.
When the letter R of paradice is placed into its only conceivable position, along with the L and V from slaves, it is reminiscent of the 'Halloween' card. What are the chances that this could be achieved accidentally?  

The word paradice travels vertically 17 lines, exactly matching the 17 columns that slaves travels horizontally.The Zodiac Killer placed crosshairs beneath the 9th column, the midsection of the cipher (shown here).
The intersection on the 'Halloween' card configuration forms RAD and LAV, exactly the same as the bisecting center point of the 340 cipher. The Zodiac Killer also underlined the LAV of Paul Averly on the Halloween card envelope, on which he also placed the intersecting "sorry no cipher" on the envelope inner. 
The 'Halloween' card stamp depicts the surface of the moon with a half-earth in the distance and the words "In the beginning God." This phrase fits perfectly on the 1st line (the beginning) of the 340 cipher, with the 15th, 16th and 17th characters uncannily similar to the word GOD (the O in half phase just like the image on the stamp). 

But this wouldn't be the only correspondence that suggested the 340 cipher was designed as a puzzle rather than a 408 style message, If the paradice and slaves connection does exist between the 340 cipher and 'Halloween' card, then it makes more sense that the design of paradice and slaves was created in the 340 cipher first, and the 'Halloween' card was to "clue us in". If not, then the observation is just happenstance.
​If the 340 cipher doesn't actually contain a message, it will never be broken, and paradoxically will remain unsolved despite no solution being possible. 
The cipher has many other issues- in that, the Zodiac Killer may have had 'cipher three' formulated or drafted before he designed 'cipher two', to enable the interconnectivity between both. He had to think forwards to create backwards.
If we assume the 340 cipher has a solution and therefore a key (no matter how complex), then one may assume the Zodiac created the key, then created the message, and then applied the message to the key, so as to encrypt it. If this were the case, we must believe that the 'near Zodiac' that emerged on line 20 was by sheer chance. We would also have to believe, that had he crafted 'cipher three' completely independent of 'cipher two', with no intention of connecting both, then the following observations also happened completely by chance.

​Although covered many times before, the following will help explain the conundrum. 
Because the '13 Symbol' cipher was thirteen characters in total (half the alphabet) and began with an A and ended with an M, it was considered that by placing the first half of the alphabet alongside the '13 Symbol' cipher and numerically counting the difference between the columns, something may emerge- It did.
For example: C to N produces a difference of 11, whereas B and E produces a difference of 3. Non alphabetical symbols cannot produce a difference, so a zero is inserted. The resulting numbers produced have been color coded. The red section is before the first circled 8, the green section is after the last circled 8 and the blue section spans the first and last circled 8. Notice the perfect symmetry. The red and green numbers are identical read forwards or backwards, and the blue numbers again read identically in either direction, producing a mirror image.
An equally symmetrical pattern was created using the identical technique, when placing the correct spelling of Zodiac alongside the 'near Zodiac' on line 20 of the 340 cipher. 
Furthermore, the three 0's and three 8's created, can be combined and carried forward onto his '13 Symbol' cipher, which seemingly is what he did.
It is also apparent on the '13 Symbol' cipher, that either side of the three circled 8's are the Zodiac crosshairs and an inverted Aries symbol, also present on either side of the 'near Zodiac' on the final line of the 340 cipher. So, the author has effectively carried eight symbols from one cipher to another.
The point being, that when the Zodiac Killer sat down at his desk and began to create a unique key for his 340 cipher, into which he was to place his message, it accidentally created the 'near Zodiac' on the 20th line, accidentally created the correlation between 'near Zodiac' and Zodiac to produce three circled 8's, accidentally created the symbols either side of 'near Zodiac,' that fully or in part, carried forward to the '13 Symbol' cipher in the correct position, and accidentally created symmetry in both instances. Or, the Zodiac crafted the '13 Symbol' cipher before or alongside the 340 cipher, which I would argue nobody believes.
The Zodiac Killer may have began his 340 cipher key from the bottom first, deliberately allocating specific letters in his message to create the 'near Zodiac' characters and continuing from there. But, if the interconnectivity exists between the 340 cipher and '13 Symbol' cipher, he effectively began with 'cipher three' first and worked backwards, and worked forwards with the words ​paradice and slaves from the 408 cipher. 

​The Zodiac may have presented us with a fictitious negro male on August 4th 1969, who by inference, provided us with some valuable information about the Zodiac Killer driving his brown car by the payphone at Springs and Tuolumne. Was this a red herring of a clue, much like the correction on line 6 of the 340 cipher.
It can be clearly seen on the left, that the Zodiac Killer was conscientious enough to correct an alphabetical K to a reversed K on line 6, even though spelling correctly was never much of an issue with the Zodiac Killer. To validate that this was a genuine mistake, he made sure that the original K had not been fully obscured. This may give the impression it is easy to mix up your K's when implementing your encrypted text. Or maybe this is what he wanted us to believe. Who in their right mind would correct a fake cipher? Therefore it must be genuine.
Did the Zodiac Killer implement this correction, conveniently leaving the blacked out character still visible (and just reversing it), to give us the impression that the 340 cipher is undeniably genuine. Was this move just another red herring, to again validate something that never was. 
Alternatively, the final line of the 340 cipher may contain just a part message, yet incomplete, bearing in mind that many believe the '13 Symbol' cipher may contain some form of a name. The 340 cipher may end with: "the Zodiac is".... to be continued on the next cipher. The anticipation of the newspapers and readers alike, for the sequel to be released, would be a Zodiac dream.
The Zodiac Killer may have been pushing us in the right direction on October 27th 1970, but his attempt at revealing the workings of the 340 cipher may have begun far earlier, on December 16th 1969- just 38 days after his 'so called' masterpiece- in which he would be claiming a potential 38 more victims.
The December 16th 1969 'Fairfield' letter, mailed to the San Francisco Examiner, has been considered dubious Zodiac correspondence, however, it may have been Zodiac's first foray into revealing the mechanics of the 340 cipher, albeit using a rudimentary code as a tool. 
Clearly, the Zodiac must have known that offering just five different symbols in a code of nine is open to many different interpretations, and hence practically unsolvable. Therefore, one could suggest this wasn't his intention- he was simply teasing us with the mechanics of how the 340 cipher was designed, by using a rudimentary diagram based on the Tim Holt comic- and something he would expand upon nearly a year later.
One can see how he uses the Zodiac symbol around the crosshairs in the December 16th 1969 'Fairfield' letter code, implying a uniformity of message, but aligns five symbols as an introduction to this design. This marries perfectly with 'Death By Gun', 'Death By Knife', 'Death By Fire' and 'Death By Rope.' Death is the introduction, following by the methods of death around the crosshairs. This is exactly what he offered us on October 27th 1970, when he placed the methods of death in the four quadrants of the bisecting Paradice and Slaves.  Here is a representation. 

Another Fairfield letter was mailed prior to this correspondence on December 7th 1969, mailed to the San Francisco Chronicle. Was the Zodiac Killer highlighting pertinent sections of the 340 code in as little as one month after his November 8th 1969 'Dripping Pen' card and cipher, negating the idea he could resist the temptation of giving us clues to its design.
The final offering to the mechanics of the 340 cipher may have come with his final confirmed correspondence- that of the 'Exorcist' letter mailed to the San Francisco Chronicle on January 29th 1974. ​         

The symbols at the foot of the 'Exorcist' letter were rearranged by Kevin Robert Brooks to reveal the words "To Kill". The message would then read "If I do not see this note in your paper, I will do something nasty, which you know I'm capable of doing...To kill."  
This threatening message was very similar to the trinity of communications that began the Zodiac's letter writing campaign on July 31st 1969, where he stated "I want you to print this cipher on the front page of your paper. In this cipher is my idenity. If you do not print this cipher by the afternoon of Fry.1st of Aug 69, I will go on a kill ram-Page Fry. night. I will cruse around all weekend killing lone people in the night then move on to kill again, until I end up with a dozen people over the weekend."  
In both the 'Exorcist' letter and July 31st communications the author would threaten "to kill'- as he would in the decoded 408 cipher. This is not particularly unusual for a serial murderer, but linking the unarranged symbols on the 'Exorcist' letter to the 340 code may connect yet another communication to the design of the cipher.
Key features of the 'Halloween' card, '13 Symbol' cipher, Fairfield communications and 'Exorcist' letter can be found in the 340 cipher, suggesting the Zodiac Killer was constantly pushing us towards the design of the 340 puzzle.
The following presentation will show a perceived correlation of the 'Exorcist' letter symbols to the only corrected section of the 340 cipher.

​​In the image on the left I have moved the two symbols on the extreme left of the 'Exorcist' letter to the right side as shown, without altering their position on the vertical axis. Then I have turned the extreme right symbol on the 'Exorcist' letter 90 degrees clockwise to form the new arrangement, shown in the bottom left image. This can now be compared to certain characters on the fifth, sixth, seventh line of the 340 cipher. The area in the proximity of the corrected sixth line.
Five of the six characters on the 'Exorcist' letter now bear a noticeable similarity to this area of the 340 cipher.
Did the Zodiac Killer sit down to create a uniform and continuous message using a code key in the 340 cipher, just like the message contained within the 408 cipher? If so, then the above findings were all created accidentally and unintentionally by the killer.
He placed an intersecting symbol at the center of the 340 cipher (+ sign), with two dashes at the periphery of the center line, to create the illusion of intersecting crosshairs.
Paradice and Slaves (uniformly of 17 characters) was created as a viable possibility bisecting the 340 cipher along the X and Y axis, along with "RAD" and "LAV" on the intersection of the cipher. The word "BY" (horizontally) was present in all four quadrants of the cipher. The 'near Zodiac' allied with the correct spelling of Zodiac on the 20th line produced the symmetry of three circled 8's. Using the identical technique and placing half the alphabet alongside the '13 Symbol' cipher, yet again, perfect symmetry was observed.
The three circled 8's, along with the symbols either side, all carried forward from the second cipher to the third cipher, and the 'Exorcist' letter symbols aligned with the corrected sixth line of the 340 cipher. This of course all happened by chance and the Zodiac Killer knew nothing about it.  
This would indicate that the Zodiac Killer had deliberately placed Paradice and Slaves into the 340 cipher, to which he would give us a clue one year later. The machinations of the '13 Symbol' cipher were most likely constructed in the mind of the killer before November 8th 1969, as to create a continuity between the two ciphers. The idea therefore, that the author of all these communications could interweave these designs together and still create a rambling uniform message to co-exist alongside them within the 340 cipher, would probably be a step too far.
The idea of a killer who sat down one evening to write a rambling 340 character message, to which he enciphered using a code key, who would then accidentally and inadvertently create so many by-products in his cipher without his knowledge, seems rather fortuitous. The Zodiac seemingly couldn't resist showing us the workings of his great masterpiece, and would eventually tell us that the 340 code was "no cipher", by giving us a portion of its true design in the 'Halloween' card on October 27th 1970. However, it's far more fun chasing a real cipher, that will long continue for another 50 years.