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

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

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

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

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

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

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.

Bringing together several articles to paint the entire picture, I would like to tell you a little story about San Jose and the major impact it had on the actions of the Zodiac Killer spanning just over two years. The attack on Bryan Hartnell and Cecelia Shepard at Lake Berryessa on September 27th 1969, inextricably linked to Debra Gaye Furlong (14) and Kathy Ann Snoozy (15), two young girls who were found murdered on August 3rd 1969 in the Bay Area of San Jose. The man ultimately convicted for these two murders in 1971, Karl Francis Werner, was the trigger behind the attack at Lake Berryessa. 

The Zodiac Killer had successfully murdered three and seriously injured one person by the time he mailed his trinity of July 31st 1969 letters to the San Francisco Chronicle, San Francisco Examiner and Vallejo Times-Herald. He then presented codebreakers with the extremely unusual challenge of deciphering three parts of one cipher from the hand of a serial killer, demanding that he receive front page coverage for his efforts. The three communications and three murders, in his mind, warranted the full attention of the American public when he wrote "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 two major news publications, the San Francisco Chronicle and Examiner, dismissed his demands by only publishing his offerings on page four and nine respectively. The Zodiac Killer's disdain was immediate, when on August 4th 1969 he presented us with his sinister pseudonym "This is the Zodiac Speaking" in a follow-up letter, that concluded with "I was not happy to see that I did not get front page coverage". But imagine his horror, when two days later the San Francisco Chronicle (August 6th 1969) ran a comprehensive front page article about the murders of Debra Gaye Furlong and Kathy Ann Snoozy in San Jose. Here is an excerpt:

The two young girls, found dead Sunday on a sun-parched San Jose hillside, appear to have been victims of a sexual psychopath, whose blood frenzy led him to "overkill". Dr. John E. Hauser, Santa Clara county's chief medical examiner and coroner, said yesterday that the girls, Deborah Gay Furlong, 14, and Kathy Snoozy, 15, died in a "frenzied flurry of knife-wounds" inflicted so swiftly that neither gave any evidence of having struggled against the attack. Dr. Hauser, so shaken by the brutality of the crime he could scarcely find words, said the Snoozy youngster had 150 wounds on her back, 50 on the front and a "storm" of punctures on her neck. Deborah's body had about 100 wounds on her back and upper front and a dozen on her neck. Dr. Hauser said he was "puzzled" by many aspects of the brutal slaying. He said neither girl had been sexually molested; neither had suffered any wounds below her waist, neither gave evidence of having struggled to escape. Only the Snoozy girl, he said, had one small mark on her hand, suggesting she may have tried vainly to deflect the plunging knife. The coroner said both girls must have died very quickly and he is investigating the possibility they may have been drugged before the stabbing began. Blood and skin samples as well as stomach contents have been sent for further examination to area laboratories, he said. The results should be known in a few days. It is Dr. Hauser's opinion that the multiple puncture wounds were inflicted by one or two small knives, the largest wound the size of a pocket knife with a half-inch blade. "I've never seen a case with this many stab wounds," Dr. Hauser said. "You know, I've been in this profession a long time and sometimes I think I'm rather callous, but when I saw these girls, believe me it was terrifying. "The Nazi sex mutilations during World War II were nothing compared to what was done to these young girls.     

The Zodiac Killer must have been incensed that despite his brutal murder of three people during the holiday season, followed by his cryptic correspondences, he failed to achieve front page coverage from the Chronicle or the Examiner, despite threatening another dozen victims over the weekend. The only difference, he must have surmised, was the method of attack and the horror that such an intimate attack with a bladed instrument on two young girls had engendered in the psyche of the newspapers and public at large. The Zodiac Killer knew at this moment he had to ratchet up his attacks and get up close and personal with the use of a knife. But this wouldn't be any ordinary attack - he would dress up in an executioner's costume and hunt for young girls armed with a 12-inch knife - not "a pocket knife with a half-inch blade". Although Karl Francis Werner's capture was two years in the making, he was the absent agent behind the attack on Bryan Hartnell and murder of Cecelia Shepard just seven weeks later. Without the murders of Debra Gaye Furlong and Kathy Ann Snoozy on August 3rd 1969, it can be argued the attack at Lake Berryessa would never have taken place.

No surprise then, that the Zodiac Killer wanted to outdo the August 3rd 1969 murders, by setting his sights on three young girls from Pacific Union College as they sunbathed on the shores of Lake Berryessa on September 27th 1969. Three murders with a 12-inch bladed knife would definitely have done the trick. But something clearly thwarted this attack and two hours later he focused in on Bryan Hartnell and Cecelia Shepard, determined not to be denied and secure his front page coverage. After the sixteen strikes into the young couple, he retreated and traveled back up the hill to lay claim to this attack as the Zodiac Killer. After writing the dates of his previous two attacks and this one on the car door of Bryan Hartnell, he emphasized the words "by knife" at the foot of the message. The Zodiac Killer was effectively saying "do I get front page coverage now". The brutal knife attack, he hoped, would get the recognition akin to the murders of Kathy Snoozy and Deborah Furlong. Not only did he get the recognition, but it had an added benefit of the newspapers considering the possibility of his involvement in the Kathy Snoozy and Deborah Furlong murders. This certainly didn't escape his attention.    

Six weeks later he duly obliged by slipping in "Aug" into his confirmed murder count when mailing the 'Dripping Pen card on November 8th 1969, bumping up his total to seven victims. The Lake Berryessa attack "by knife" had effectively secured him two more victims by association. But to cement his perceived involvement in the San Jose murders, he had to strike while the iron was hot.

On November 21st 1969 he mailed a threatening letter to the San Jose Police Department beginning with the words "There's no doubt I will do my Thing!". The letter initiated this response: 'For the information of the Bureau and Sacramento, after a cursory analysis, officers of the San Jose, California PD, believe widow in message may be Mrs (redacted), San Jose, California. San Jose PD instituting 24 hour surveillance on Mrs (redacted).' It is clear that this woman had some connection to the Snoozy and Furlong murders, and by the Zodiac Killer interjecting himself into the San Jose investigation, he was attempting to solidify the notion of his involvement in them. Bearing in mind this letter was mailed to the San Jose Police Department and their response to secure the woman's safety, it isn't too surprising that the Zodiac Killer would threaten to murder a San Jose policeman in the Fairfield letter mailed a month later, on December 16th 1969. The Zodiac Killer thought he had now successfully cemented his claim to the Snoozy and Furlong murders. His choice of switching from gun to knife had paid dividends. My guess, is he was banking on these murders never being solved.

Imagine the Zodiac Killer's dismay in late April of 1971, when his plans lay in tatters, upon the arrest of Karl Francis Werner for the April 11th 1971 murder of Kathy Bilek at Villa Montalvo in Saratoga, as well as the murders of Kathy Snoozy and Deborah Furlong in San Jose two years earlier, on August 3rd 1969. The Zodiac Killer would eventually be exposed as a fraud - caught in the act of claiming somebody else's victims at last. He reacted forthwith, by mailing two communications to the San Francisco Chronicle in the middle of 1971. 

In the first, he was trying vainly to convince us that he was in fact the murderer of all three girls (Snoozy, Furlong and Bilek) by claiming that Karl Francis Werner was the fraud or phony. Paul Avery, arch nemesis of Zodiac, wrote an article on April 30th 1971 detailing the capture of Werner. The newspaper article stated "He (Werner) was immediately advised of his rights concerning any statements he may make and legal representation to which he is entitled, the detectives said. Werner was then taken to the scenes of the crimes. Late yesterday he was undergoing questioning. The detectives would not reveal what statements, if any, he had made concerning the killings of the three girls". 

The Zodiac Killer responded sometime after he read this article (around May, June or July of 1971), mailing a 148 character cipher stating "Tis the Zodiac Speacking. Why can't you stop me. I can't stop killing. Stop listening t(o) phonys. If this is not on your front page in a week I will skin 3 little kids and make a suit from the skin". In this correspondence he claimed his victim count was 21, by writing "I done it 21 times". This, in accordance with his claimed victim count of 17+ in the March 13th 1971 'Los Angeles' letter. We can ascertain that this communication was mailed around the middle of 1971, because he fired off a second correspondence at about the same time. The correspondence about to be discussed was withheld from newspaper publication (as was the 148 character cipher), so the fact that both contained a victim count of 21 and mailed in close proximity to one another, should be enough to consider both being mailed by the Zodiac Killer. The second communication we will show, is not only trying to claim the murder of Kathy Bilek - again attempting to show that Karl Francis Werner was a phony - but is also linking itself to the murders of Snoozy and Furlong.    

On July 13th 1971 a pasted card was mailed to the San Francisco Chronicle with the words "Near Monticello Shought Victims 21 ...... In The Woods Dies April". Many have speculated on the location mentioned in the card as "Monticello" in Napa County, California, because of the Lake Berryessa attack on Bryan Hartnell and Cecelia Shepard on September 27th 1969. It has been further speculated on whether "April" was a woman's name or the month of the alleged murder. After a comprehensive review of all the information, I believe the woman's identity, labelled as victim number 21, can finally be revealed, along with the exact location of Monticello. 

On Sunday, April 11th 1971, Kathy Bilek (18) visited Villa Montalvo in Saratoga, having planned to read a paperback book (The Gabriel Hounds) and engage in a spot of bird watching​ in the seclusion of a remote, wooded portion of the park, near a small stream. Her body was found the next day by her father, Charles, while Santa Clara County Sheriff's deputies searched nearby. She had been stabbed 17 times in the back and 32 times in her chest and stomach, although her killer had taken care to avoid stabbing her breasts. Her murder was also attributed to Karl Francis Werner. Wikipedia. The brutal murder of Kathy Bilek would again be claimed by 'Zodiac', not only in the Monticello card, but in another alleged Zodiac letter, also mailed to the San Francisco Chronicle at about the same time as the Monticello card. Kathy Bilek was murdered in "April", exactly as mentioned in the Monticello card, and "in the woods" at Villa Montalvo (a wooded section of the park). Saratoga is a city in Santa Clara County, California, United States. It is located on the west side of the Santa Clara Valley, directly west of San Jose, The appearance of San Jose once again. ​ ​

It was easy to get sidelined into believing Monticello was referring to Napa County, because the town was completely covered by Lake Berryessa, the site of Zodiac's third attack. However, the "Monticello" the author is referring to in the pasted card, is again in San Jose. Monticello is a neighborhood in San Jose, California, just over 9 miles east of Villa Montalvo, the site of Kathy Bilek's murder. ​In other words, the author of the card was saying "I killed Kathy Bilek near Monticello, in the Villa Montalvo woods in April". ​To view the proximity of Monticello to Villa Montalvo click here.

The Monticello card stated "Shought victims 21", referring to the Kathy Bilek murder, whereas, in the 148 character cipher, the author was claiming he had already "done it 21 times." The Monticello card was never released to the newspapers or public, so bearing in mind these two communications were both likely mailed at approximately the same time, there is a high probability they were mailed by the Zodiac Killer.

"I killed Kathy Bilek near Monticello, in the Villa Montalvo woods in April".
"Near Monticello Shought Victims 21 ...... In The Woods Dies April".

The ​November 8th 1969 'Dripping Pen' card would not be the only communication insinuating his involvement in the murder of Deborah Gaye Furlong and Kathy Ann Snoozy, when the Monticello card arrived just over 20 months later, on July 13th 1971. The San Francisco Police Department had reason enough to place the Monticello card in 'suspected Zodiac correspondence' when searching for traces of DNA on potential Zodiac communications, indicating the high regard it was held in.

It is with little doubt that Karl Francis Werner was responsible for the murder of Deborah Furlong, Kathy Snoozy and Kathy Bilek in 1969 and 1971, but the overarching question is, why did the Zodiac Killer describe the location of Kathy Bilek's body as "near Monticello"? The neighborhood of Monticello is 9 miles east of Villa Montalvo. Why did the Zodiac Killer choose to pinpoint this particular location, rather than any other neighborhood in between Monticello and Villa Montalvo? He could have pasted "near Willow Glen", "near Oster", "near Carlton", or any other location closer than Monticello. It is arguable that he chose this particular location for a specific reason.   ​

Tom Voigt, creator of the hugely successful Zodiackiller.com website has sought a potential Zodiac letter, described as the DMV letter. On his message board he stated "While I don't yet have as many details as I would like, at some point the Zodiac wrote a letter to the chairman of the Department of Motor Vehicles (DMV) in California. The letter was authenticated, apparently via handwriting, and was kept quiet for reasons unknown". None of the following can be definitively proven, but I will attempt to expand on this elusive correspondence based on the limited information we have, and use the propensity of the Zodiac Killer to respond to newspaper and magazine articles against him. We know he closely followed anything that was written about him and often replied in kind. With that said, it is possible the DMV letter was mailed to the chairman of the Department of Motor Vehicles because he read an article referencing this department. If the letter was addressed to the chairman, it is very likely the letter was addressed to the headquarters of the DMV in Sacramento. What we now have to do, is tie the Sacramento DMV to a Zodiac crime, or a crime claimed by Zodiac, written in a publication that the Zodiac Killer had reason to read - who subsequently got upset because it portrayed him as a liar and a fraud. It therefore follows, that it is highly unlikely to be a polite correspondence from the Bay Area killer. Based on the above, I believe the DMV letter was mailed in the October or November of 1971.

As early as November 8th 1969 the Zodiac Killer was claiming the murders Deborah Gaye Furlong (14) and Kathy Ann Snoozy (15), who were found murdered on August 3rd 1969 in the Bay Area of San Jose. This was his "Aug" on the 'Dripping Pen' card. He would later insinuate his involvement in the murder of Kathy Bilek (18), murdered in the woods of Villa Montalvo in Saratoga, due west of San Jose. On July 13th 1971, a potential Zodiac communication arrived in the form of a pasted card. It read "Near Monticello Shought Victims 21 ...... In The Woods Dies April". The author of the card was detailing the murder of Kathy Bilek in the woods of Villa Montalvo on April 11th 1971, just 9 miles from the neighborhood of Monticello in San Jose. He chose this neighborhood because it sat adjacent to Oak Hill Memorial Park at 300 Curtner Avenue. The cemetery where the body of Kathy Ann Snoozy lay - and chosen to hint at the forename "Kathy", pertaining to Kathy Bilek.

​Assuming these communications were mailed by the Bay Area murderer, it would be fairly obvious that the Zodiac Killer was following the San Jose murders closely from August 3rd 1969, through his 'Dripping Pen' card of November 8th, to the eventual murder of Kathy Bilek, and up to his correspondences in the middle of 1971. Therefore, it would be no great surprise if he continued to monitor any newspaper or magazine articles regarding the murders of the three young females. ​

In October 1971, a magazine publication entitled 'True Detective' comprehensively featured the murders of Kathy Snoozy, Deborah Furlong and Kathy Bilek, and the subsequent arrest of Karl Francis Werner. There is every chance the Zodiac Killer read this magazine article, compelling him to continue his contact with authorities regarding these murders.

One particular section about Kathy Bilek caught my eye - that may have been the reason why the Zodiac Killer wrote a letter to the chairman of the DMV in Sacramento. It stated "At about the same moment, Park Ranger Ken Williamson was informing a member of the investigative team that he, too, had noticed a tall, bespectacled young man who had been a frequent visitor at Villa Montalvo. He was a loner and had impressed the Villa's ranger staff with his almost furtive conduct, said Williamson. The ranger had jotted down the license number of the strange youth's auto.
The license number was forwarded to the California Department of Motor Vehicles headquarters in Sacramento, the state's capital 150 miles to the north of San Jose. The information teletyped back from the registration bureau was that the auto was the property of a Karl Francis Werner, living at an address on Shawnee Lane in San Jose." 

The Zodiac Killer, having previously mailed two communications (Monticello card and 148 character cipher) referencing the murder of Kathy Bilek and the victim total of 21, it wouldn't be at all surprising if he fired off a third communication, this time to the Department of Motor Vehicles in Sacramento, after reading these two paragraphs. As this magazine article was published in October of 1971, the DMV letter may have been postmarked with the latter months of that year - possibly October, November or December. The compunction of the Zodiac Killer in claiming, or interjecting himself into the middle of these murders, may have been the driver behind his contact with the chairman of the DMV. The content of this communication is unknown, but I guess he is continuing the menacing theme of his previous two correspondences, suggesting the identification of the vehicle belonging to Karl Francis Werner is somehow another red herring and threatening more murder and mayhem.

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

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

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

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

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

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

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

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

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

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

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

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. 

Using old and new material, we will take a comprehensive look at the 'Dripping Pen' card mailed by the Zodiac Killer on November 8th 1969, and attempt to link it to a future threat of murder. The card itself was most likely chosen for purpose, referencing the immediate aftermath of the attack on Bryan Hartnell and Cecelia Shepard at Lake Berryessa on September 27th 1969. Approximately five minutes after the brutal stabbing, the killer walked to the side of Bryan Hartnell's white Volkswagen Karmann Ghia and wrote "Vallejo 12-20-68, 7-4-69, Sept 27-69 -6:30 by knife". The hand the killer wrote on the car door with, was likely the hand he used during the attack on the young couple, almost certainly peppering his dominant hand with blood, and consequently to the marker pen he wrote with. So, the choice of greeting card stating "Sorry I haven't written, but I just washed my pen" was likely a sardonic reference to the callous and bloody attack at Lake Berryessa. The addition of "Aug" on the card inner, a suggestion of his involvement in the double murder of Deborah Furlong and Kathy Snoozy in San Jose on August 3rd 1969. This, coupled with the footnote of "by knife" written on the car door, was likely deliberately engineered to steer investigators toward this conclusion. They had after all considered this premise in the October 1st 1969 edition of the San Francisco Examiner, in which was stated "And today San Jose police, to the south, inquired of law enforcement officers here whether there was indication that the "Cipher Killer" might be linked to the knife slaying of two teenage girls Aug.3, still unsolved". This wouldn't be forgotten by the Zodiac Killer.   

Another reason to believe the 'Dripping Pen' card was referring to Lake Berryessa can be found in its design. The Zodiac Killer, almost without exception, would give us a running total of his victims, occasionally writing the victim count on the horizontal wing of the crosshairs. The only two times this was not the case, was the November 8th 1969 'Dripping Pen' card and the car door of Bryan Hartnell's white Volkswagen Karmann Ghia. In both of these writings he gave us his Zodiac crosshairs with the months of his murders underneath. This was the first and last time he would ever do this.

If you run the message from the face of the 'Dripping Pen' card to inner, it reads "Sorry I haven't written, but I just washed my pen and I can't do a thing with it". So, when the Zodiac Killer wrote "I get aufully lonely when I am ignored, so lonely I could do my Thing", he was indicating that in the future when he needed some attention, he would write again. His Thing being his propensity to put pen to paper, or in the case of Lake Berryessa, to metal. He was effectively addressing the police when he wrote "I though you would need a good laugh before you hear the bad news. You won't get the news for a while yet". In fact, the bad news would arrive in exactly thirteen days time - and it was directed towards the police in regards to the month of August. In effect, his next correspondence would be pushing the same narrative as the car door and greetings card, of his involvement in the deaths of Deborah Furlong and Kathy Snoozy. 

​On November 21st 1969, a letter arrived at the San Jose Police Department, addressed to a particular law enforcement officer. The letter was threatening a widow - so much so - that police initiated 24-hour surveillance on the woman's home. The police stated that "they believed the widow in the message may be Mrs......" In other words, the woman wasn't directly named in the correspondence, but they had by reasonable deduction, concluded who the threat was aimed at. I believe that the Zodiac Killer, in his continued drive to cement the notion of his involvement in the two teenage girls murders, mailed this "bad news" to the San Jose Police Department. Can it really be a coincidence that he wrote "by knife" on the car door to plant the seed, added the "Aug" on the 'Dripping Pen' card, then mailed his next correspondence to the City of San Jose? In addition, this new communication began with some familiar words: "There's no doubt I will do my Thing".  

On November 21st 1969, the San Jose Police Department would still have been devoting many hours to the unsolved murders of these two teenage girls, and likely receiving many tips from potential eyewitnesses and the residents of San Jose, eager to assist in the investigation. What better way for the Zodiac Killer to convince law enforcement of his potential involvement in this crime, by threatening to do his Thing on one of these residents.

I have no doubt the Zodiac Killer was scouring the newspapers about this crime - so imagine he came across such a headline:
"An elderly widow, Maureen Jones, was today helping police with their investigation into the senseless murders of two young girls in San Jose, Sergeant Johnston said", or "An elderly widow, residing at Seacreek Way, was today helping police with their investigation into the senseless murders of two young girls in San Jose, Sergeant Johnston said". These article excerpts are fictitious, designed to show what Zodiac  may have read in any number of articles I have no access to. 

The Zodiac Killer never mentioned his victims by name, so it is entirely plausible that whether he knew this woman's name or not, he could, by sending a threatening letter to police using the term "widow", and addressing the communication to "Sergeant Johnston", convince police that the threat was a credible one. This may be why the police believed they knew who the woman was, despite the fact her name was never mentioned in the correspondence mailed to the San Jose Police Department. Because she had recently received newspaper coverage.     

A small code arrived with the November 21st 1969 communication. The short code (shown above in the FBI files) was
​-- + 6 2 + --, containing two dashes either side, two pluses, and the numbers 6 and 2. The idea that anybody looking at this code could arrive at 1620, without having previous reason to suspect this four number solution, seems unlikely. But if investigators knew that "Maureen Jones" lived at a residence, such as 1620 Seacreek Way, San Jose, then they might have reason to believe this is what the code was implying. Earlier newspaper reports stated "A killer armed with a thin-bladed stiletto was hunted here today as the one who savagely stabbed to death two teenage girls yesterday as they picknicked in Almaden Valley. The scene where the bodies were found is just south of Blossom Hill Road, two blocks west of Calahan in the northern end of the valley. About 10:00 am yesterday, the girls packed a lunch and left Deborah's parents' San Jose home for a picnic atop a grassy knoll nearby. The picnic ground is a rugged area, near a narrow, serpentine trail used by motorcyclists for hill-climbing contests".  So, if we could find a 1620 residence in San Jose, possibly close to the crime scene, this may be the location of the "widow" Zodiac was targeting.

As shown above, in the October 1st 1969 San Francisco Examiner article, "San Jose police, to the south, inquired of law enforcement officers here whether there was indication that the "Cipher Killer" might be linked to the knife slaying of two teenage girls Aug.3".  Therefore, would it really be that surprising if the Zodiac Killer had capitalized on their suspicions and mailed a threat to the San Jose Police Department? He knew he would be taken seriously by police - and why they were prepared to instigate 24-hour surveillance on the residence of the "widow" mentioned in the letter.

In the last article 'More Than Just By Knife' we looked at the message "by knife" on the car door at Lake Berryessa and the month of "Aug" on the 'Dripping Pen' card, mailed on November 8th 1969. It was argued that the reference to "by knife" meant so much more to the killer than just telling us the patently obvious, that Bryan Hartnell and Cecelia Shepard were attacked with a knife. It was a declaration of what was soon to be revealed on November 8th 1969, that the Zodiac Killer was suggesting his involvement in the Kathy Snoozy and Deborah Furlong double stabbing on August 3rd 1969.  

The addition of the time on the car door also appeared to be lacking any great purpose, so this led me to believe that the time of 6:30, just like "by knife", also had some significance to the killer. The Zodiac Killer would certainly have been scouring the newspapers around the time of his July 31st 1969 and August 4th 1969 communications to the San Francisco Chronicle, San Francisco Examiner and Vallejo Times-Herald. It is apparent that his narcissistic tendencies would have compelled him to purchase the newspapers for any reading material about himself. 

It must therefore have annoyed him greatly that the Kathy Snoozy and Deborah Furlong murders featured on the front pages of the San Francisco Examiner on August 4th 1969 and the San Francisco Chronicle on August 6th 1969, when he had declared at the same time that he "was not happy to see that he did not get front page coverage" in the 'Debut of Zodiac' letter. This is probably the moment he decided on an altogether more hands-on approach to his method of murder - by knife. The inspiration for the Lake Berryessa attack may have come straight from the pages of the San Francisco Examiner. On the same day the Zodiac Killer hand delivered his 'Debut of Zodiac' letter to the Examiner offices, the San Francisco Examiner headlined with '2 Girls Stabbed-Picnic Murders Footprint Clue'. Apart from "Girls", this headline could easily have been written for the September 27th 1969 Lake Berryessa attack.       

Bryan Hartnell and Cecelia Shepard were enjoying a pleasant afternoon/early evening picnic near the Oak Shores Recreation Area, when a man in an executioner's outfit changed everything. The San Francisco Examiner (above) stated "San Jose-A killer armed with a thin-bladed stiletto was hunted here today as the one who savagely stabbed to death two teenage girls yesterday as they picknicked in Almaden Valley. The scene where the bodies were found is just south of Blossom Hill Road, two blocks west of Calahan in the northern end of the valley. About 10:00 am yesterday, the girls packed a lunch and left Deborah's parents' San Jose home for a picnic atop a grassy knoll nearby. The picnic ground is a rugged area, near a narrow, serpentine trail used by motorcyclists for hill-climbing contests". 

​The question being: did the Zodiac Killer switch from gun to knife, head down the serpentine trail of Lake Berryessa to target unsuspecting picknickers or people enjoying a relaxing day out, because he just fancied a change, or did he believe this was his path to guaranteed "front page coverage", just like the brutal stabbing of the two young girls in San Jose? The car door may have held the answer, by the addition of the "by knife" phrase. The Zodiac Killer was effectively saying "do I get front page coverage now". But how does the time of 6:30 (pm) on Bryan Hartnell's car door play into the Kathy Snoozy and Deborah Furlong murders of August 3rd 1969.

Serial killer Karl Francis Werner may inadvertently have been responsible for the murder of Cecelia Shepard and attempted murder of Bryan Hartnell at Lake Berryessa on September 27th 1969. Many people have made the case for questioning the Lake Berryessa attack as a Zodiac crime, by pointing out that the Zodiac Killer included the month "Aug" on his November 8th 1969 'Dripping Pen' card, yet he failed to include this date on the car door of Bryan Hartnell's white Karmann Ghia. However, the inclusion of August on the 'Dripping Pen' card may be the confirmation of the "by knife" message on the car door withheld by police. As early as October 1st 1969, only four days after the Lake Berryessa attack, an article in the San Francisco Examiner entitled 'Sex Fiend Sought For Six Killings' stated "A psychotic killer police say brutally slays females for sexual gratification is loose in the North Bay today". Extremely irresponsible and factually incorrect journalism, that may have driven the attack on a lone male in San Francisco to prove this assertion incorrect.

The Zodiac Killer would use this "North Bay" reference only twelve days later, after the callous execution of taxicab driver Paul Stine on October 11th 1969 in San Francisco, to confirm his link to Berryessa. The Zodiac Killer mailed a letter to the San Francisco Chronicle with the admission "I am the same man who did in the people in the north bay area". The San Francisco Examiner would detail the withholding of part of the message on the car door at Berryessa, stating "There was more to the inked car door message than dates. But Captain Townsend masked the information, considered it "classified". In the September 30th 1969 edition of the Examiner, entitled 'Police Dare Cipher Killer', Captain Don Townsend dared him to write or phone again to prove he wrote the message: "There is more, and we are not releasing it now. Why? Because this man has a pattern of contacting the police and newspapers by phone and letter after his killings. We are holding back part of the note because, when and if he writes, he can say what else was written there - and thus prove he is the 'man who loves to kill'"   

I believe the Zodiac Killer did respond - not as the police had hoped - but indirectly, by the inclusion of the month of "August" on the November 8th 1969 'Dripping Pen' card, just five weeks later. The killer wrote "Des, July, Aug, Sept, Oct = 7". The murders in December, July and October were all perpetrated with a firearm, and police knew that September represented the Lake Berryessa attack with a knife. Therefore, it left "Aug" to figure out.

​The answer lies in the October 1st 1969 San Francisco Examiner edition, where investigators contemplated a link to the brutal stabbing and murder of two young girls in San Jose on August 3rd 1969. Deborah Gaye Furlong (14) and Kathie Ann Snoozy (15) were found murdered in the Bay Area of San Jose, in what can only be described as a barrage of knife wounds. These murders were eventually linked to the hand of Karl F. Werner, who was also convicted of the Kathy Bilek murder. However, these murders were not solved until 1971. The October 1st 1969 Examiner stated "And today San Jose police, to the south, inquired of law enforcement officers here whether there was indication that the "Cipher Killer" might be linked to the knife slaying of two teenage girls Aug.3, still unsolved".   

This is exactly what the Zodiac Killer had hoped - and why he perpetrated the Lake Berryessa attack in the first place. He was laying the seeds for law enforcement to conclude this very idea - and the reason he switched to a knife attack on this occasion. The "Aug" reference was pushing law enforcement to conclude he was responsible for the brutal slaying of Kathy Snoozy and Deborah Furlong - "by knife" - and therefore, in his mind, unequivocally linking himself to the Lake Berryessa stabbings. Had Karl Francis Werner not killed Kathy Snoozy and Deborah Furlong, it is my contention that Cecelia Shepard would still be alive today.

The Zodiac Killer knew that he had to kill to secure the attention of the newspapers, and the bolder the attack, the more publicity he would generate. He had murdered three young people by July 4th 1969 and had sent newspapers a trinity of communications on July 31st 1969 containing three parts of a cipher, determined to secure the headlines he felt he deserved. His letters promised more murder 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". To his dismay, he felt he was being short-changed, writing in the August 4th 1969 'Debut of Zodiac' letter "I was not happy to see that I did not get front page coverage". At this point in time, without doubt, the Zodiac Killer would have been scouring the newspapers for progress on solving his cipher, along with updates on his crimes. Then came the savage knife attack on Kathy Snoozy and Deborah Furlong in San Jose, featured on the front page of the San Francisco Chronicle on August 6th 1969: ​   

The Zodiac Killer likely read this article and knew the course of action he needed to take to secure "front page coverage". His next crime had to be bolder, more savage and more personal - using a knife. The brutal murder of these two young girls by Karl Francis Werner would ultimately change the tactics of the Zodiac Killer in his relentless pursuit of notoriety. Seven weeks later he arrived on the shores of Lake Berryessa.

It has been questioned as to why the Zodiac Killer wrote "by knife" on the car door of Bryan Hartnell's vehicle, when it was patently obvious the couple had been stabbed with a knife. But it was much more than this. The writing of "by knife" on the car door was a statement to the publicity he felt he deserved - and was also partly alluding to the Snoozy and Furlong murders he would lay claim to just six weeks later. The "Aug" reference on the November 8th 1969 'Dripping Pen' card was further corroboration to the 'hidden' message on the car door of Bryan Hartnell. The Zodiac Killer attacked Bryan Hartnell and Cecelia Shepard with a knife at Lake Berryessa, then planted the seed on the car door to hint towards the San Jose murders just seven weeks earlier, to which he would finally confirm on his 'Dripping Pen' card at the beginning of November. He knew the month of August would be interpreted by law enforcement as the murder of Snoozy and Furlong, because law enforcement had contemplated the link only weeks earlier. The "by knife" message on the car door at Lake Berryessa, would on November 8th 1969, now hold much more significance than it did on September 27th 1969. 

Confirmation of the Snoozy and Furlong "August" link, would arrive on July 13th 1971, when a pasted card was mailed to the San Francisco Chronicle with the words "Near Monticello Shought Victims 21 ...... In The Woods Dies April". The Zodiac Killer was now claiming (or at the very least associating himself with) Karl Francis Werner's third victim, Kathy Bilek. On Sunday, April 11th 1971, Kathy Bilek (18) visited Villa Montalvo in Saratoga, with the intent to read and engage in a spot of birdwatching in the seclusion of a remote, wooded portion of the park, near a small stream. Her body was found the next day by her father, Charles, while Santa Clara County Sheriff's deputies searched nearby. She had been stabbed 17 times in the back and 32 times in her chest and stomach. The Zodiac Killer's requirement to associate himself with three brutal stabbings, despite the fact he wasn't responsible for any, tells you all you need to know regarding his quest for notoriety - and why he was only too willing to write "by knife" on the car door at Lake Berryessa.on September 27th 1969. Its meaning went far beyond the obvious.      

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

Thirteen days after the Zodiac Killer mailed the 'Dripping Pen' card and 340 cipher on November 8th 1969, another letter and code purporting to be from the Bay Area murderer was mailed to the San Jose Police Department on November 21st 1969, possibly containing a threat on a "widow" in the San Jose area. Both mailings have so much in common, along with the December 7th and 16th 1969 Fairfield letters, which also contained rudimentary codes. The Zodiac Killer wrote the chronological months of his murders at the foot of the 'Dripping Pen' card: "Des, July, Aug, Sept, Oct = 7". Bearing in mind that all but August were accounted for, it is now clear the card was inferring the murders of two young girls, Deborah Gaye Furlong (14) and Kathy Ann Snoozy (15), who were found savagely stabbed on August 3rd 1969 in the Bay Area of San Jose. It is therefore no surprise that his next communication should be focused on San Jose just two weeks later. Below is part of the FBI file revealing some of its contents.

Placing "November=8" could be viewed as an extension to his "Des, July, Aug, Sept, Oct = 7", indicating he was claiming another murder in November. He also began the communication with familiar words: "There's no doubt I will do my Thing". As the communication was mailed to the San Jose Police Department, we would now have three victims in San Jose to which he was laying claim to. The short code (shown above) was -- + 6 2 + --, containing two dashes either side, two pluses, and the numbers 6 and 2. Both Fairfield letters contained rudimentary codes pertaining to the 340 cipher, as though he was giving us a clue to its design. This may also have been the case when he mailed the Halloween card on October 27th 1970, intersecting the words Paradice and Slaves in a cross formation and writing "sorry no cipher" in similar fashion on the envelope. In fact, the December 16th 1969 Fairfield letter contained a design similar to the Halloween card. The 340 cipher can be shown to accommodate the words Paradice and Slaves, bisecting the cipher horizontally and vertically across its mid-section. This opened up the possibility that the San Jose code was somehow connected to this design. Both Fairfield letters harked back to the 340 cipher, so why not the San Jose code also.  

The symbols contained in the San Jose code exactly mirror the order shown on the horizontal mid-section of the 340 cipher. The 10th line is where some believe the cipher could be divided, along with the possibility of the word Slaves residing. Not only do the dashes and pluses line up exactly with the San Jose code using the mid-section of the 340 cipher, but the numbers 6 and 2 would slot nicely in between. If we used basic number play, and converted 6 to F and 2 to B, both these letters can be found together on the 10th line also. All six characters from the San Jose code present on the Slaves line of the 340 cipher. 

This may very well be coincidence, but with "There's no doubt I will do my Thing", "November=8" and this correspondence immediately following the 'Dripping Pen' card and 340 cipher, one could argue the Zodiac Killer was dropping us hints to the mechanics of his "crackproof" cipher. Something he would again do with the arrival of both Fairfield letters in December.

The Zodiac Killer could wait only one month after the Button letter, to give us further clues regarding the bomb he claimed to have buried, when he wrote "P.S. The Mt. Diablo code concerns Radians + # inches along the radians". Why should the San Jose and Fairfield letters be any different?   

On October 27th 1970 the Zodiac Killer mailed the Halloween card to the San Francisco Chronicle, stating "sorry no cipher" in the form of a cross, and fashioning "Paradice" and "Slaves" in the same manner. In the four corners he placed By Fire, By Gun, By Rope and By Knife. For anyone who believes the September 27th 1969 Lake Berryessa attack was at the hand of the Zodiac Killer, must surely conclude the "by knife" reference on the Halloween card to be admitting his participation in this crime, as this phrase on the car door had been withheld from the public and newspapers alike. This inextricably links the author of the Halloween card to the Lake Berryessa attack. Elements of the Halloween card can be found in the 340 cipher, with "Paradise" and "Slaves" bisecting the cipher (17 X 17) horizontally and vertically, with the word "by" placed horizontally in each of the four quadrants. 

The Halloween card alliance to the Lake Berryessa attack formed "by knife", in conjunction with the knothole in the tree and the wording "peek-a-boo you are doomed", should leave little doubt the two are connected. There is also a strong connection from the Halloween card to both the December 7th 1969 and December 16th 1969 Fairfield letters, and in turn, all three to the 340 cipher. The December 16th 1969 Fairfield letter contained a crude arrangement of 9 symbols (10 including the large crosshairs), impossible to decode as it stood. The four crosshairs around a larger version looked extremely similar to the Halloween card arrangement - and bearing in mind the December 16th 1969 Fairfield letter was accompanied by a crude drawing of a knife entitled "The Bleeding Knife of Zodiac", it seemed likely the short code may have been Zodiac's initial attempt at revealing the hidden words on the car door of Bryan Hartnell's 1956 white Karmann Ghia. 

Thanks to Tahoe 27's excellent find linking the Halloween card to a Tim Holt comic book, depicting Death By Fire, Death By Gun, Death By Rope and Death By Knife, it seemed obligatory to consider the connection from the Halloween card "by knife" to the "The Bleeding Knife of Zodiac", along with the similarity in design between the Paradice/Slaves arrangement and the four crosshairs circling a larger version. The four methods of death represented by the four crosshairs or targets.   

The Halloween card, 340 cipher and both Fairfield letters seemed intertwined. The fact that Zodiac placed "sorry no cipher" in the form of a cross rather than just singularly, can be linked to "Paradice" and "Slaves", and therefore the 340 cipher. Was he suggesting the 340 cryptogram was not a true cipher? It appeared he may have been dropping clues to the design of the 340 cipher as early as December 7th 1969, placing a 38 character code in the first Fairfield letter.

On the left, "by" can be observed in all four quadrants. Parts of the December 7th 1969 code are highlighted in blue, while four of the adjacent symbols from the December 16th 1969 code are highlighted in yellow.

The December 7th letter opened with the words "I just need help", reminiscent of the December 20th 1969 Melvin Belli letter, and followed by "I will kill again, so expect it any time the will be a cop", similar in fashion to the April 20th 1970 letter, where Zodiac stated "But there is more glory in killing a cop than a cid because a cop can shoot back". The December 16th letter opened with the same two words as the December 7th letter, stating "I just want to tell you", almost certainly tying them together - along with the handwriting and crude coding. Bearing in mind neither of the Fairfield letters appeared in the newspapers, it appears that Zodiac either just accidentally mirrored these communications with the subsequent December 20th 1969 and April 20th 1970 letters, or he was the author of all four.

Was the Paradice, Slaves, By Fire, By Gun, By Rope and By Knife configuration a representation of the number of murders he was intending to secure for the afterlife. Paradice, Slaves, By Fire, By Gun, By Rope and By Knife oddly contained 38 letters. The character count on the December 7th 1969 Fairfield letter code was 38. The intended victims on the December 16th 1969 Fairfield letter was 38. The 340 'Dripping Pen' card, eerily similar to the "Bleeding Knife of Zodiac" depiction, opened with the wording "Sorry I haven't written, but I just washed my pen." This phrase again contained the words "I just", but also an alphanumeric count of 38. The April 20th 1970 letter, stating "I hope you have fun trying to figgure out who I killed" had a code that added up to 38 when the alphabet was placed alongside it.
And finally, the Exorcist letter (widely believed to be the final offering by the Zodiac Killer) claimed 37 victims, but promising to kill again if his demands were not met. Probably coincidence, but curious nonetheless.  

The 'Dripping Pen' card may have been a depiction chosen by the Zodiac Killer regarding his exploits at Lake Berryessa. The pen dripping blood as he is writing on the car door of Bryan Hartnell's vehicle, and his reason for washing it. The 340 cipher accompanying this card, with the "Paradice", "Slaves" and "by knife" link back to the Halloween card, further indicating a connection to Lake Berryessa through these communications. 

​The 'Death By Fire, Death By Gun, Death By Rope and Death By Knife' agenda could have been formed in the mind of the killer as early as the beginning of his campaign of terror, when he mailed the 408 cipher, stating  "the best part of it is that when I die I will be reborn in paradise 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 same paradice and slaves permeating through much of his correspondence, and possibly the 340 cipher also. "By knife" an integral part of both Fairfield letters and the Halloween card, to hopefully lay any doubts to rest, of his involvement and knowledge of the writing at the foot of the message on Bryan Hartnell's car door.

The December 16th 1969 "knife," in a side-by-side comparison to the writing on the car door of Bryan Hartnell. Anyone could have read about the Lake Berryessa attack on Bryan Hartnell and Cecelia Shepard with a knife, but would an impostor have emphasized it in the form of a drawing, as to signify its importance, without knowing for certain the hidden message on the car door? And how would the Zodiac Killer, when designing the Halloween card, accidentally mirror the "death by fire, gun, rope and knife" arrangement on the Fairfield letter, when the December 16th 1969 letter was never published in the newspapers. Somebody attempting to imitate the Zodiac Killer in both December letters, would surely have attempted to imitate him, not go out of their way to undo the neatness and organization exhibited by the 340 cipher and thereby nullify their efforts? The Zodiac Killer would have had no such concerns.

Here I would like to return to an old topic with a fresh approach, partly inspired by 'Nobody,' a regular contributor to this site.
As early as August 10th 1969 Professor D.C.B. Marsh of the American Cryptogram Association (ACA) was commenting on the Zodiac ciphers. In the San Francisco Sunday Examiner & Chronicle he praised Donald Harden's deciphering skills and called the code "complicated and obviously drawn by somebody who knows his business". 
​
The Zodiac Killer had already responded to prompts by Vallejo Police Chief Jack Stiltz to send more details to prove the letter writer and killer were one and the same. The more the Zodiac Killer wrote, not only lessened his time for killing, but may have provided additional clues to detectives regarding his identity. This tactic was likely adopted by Professor D.C.B. Marsh in the October 22nd 1969 San Francisco Examiner newspaper article by Will Stevens, which 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." 

Clearly, Dr. Marsh and the detectives would have considered it highly unlikely for the Zodiac Killer to respond by giving us his name, but while he was constructing ciphers he wasn't murdering innocent civilians. There also remained an outside chance that Zodiac would rise to the challenge and create a code, "however complicated", that Dr Marsh and his fellow cryptographers could unpick. This article, rather than a straightforward challenge to Zodiac, could have been deliberately manufactured with the assistance of detectives, to bait the Zodiac Killer into using a particular methodology in his cipher construction. If the police knew the source of Zodiac's inspiration, then it could unearth the cipher technique he employed when designing his next code. 

'Nobody' considered the idea that the Zodiac Killer may have used a foreign language in the cipher, or possibly a rotating key that switches at certain intervals. By employing such a technique, the Zodiac Killer could make the cipher virtually "crackproof". 
The article in the October 22nd 1969 San Francisco Examiner may have been specifically designed to lead the Zodiac Killer down a particular path, making his next cipher easier to crack. Dropping innocuous sections of text into an article such as "to quote Edgar Allen Poe, that any cipher created by man can be solved by man", can be specifically designed to guide the Bay Area murderer into using one of Edgar Allan Poe's cipher techniques or a model suggested by him. We know the Zodiac Killer was an avid reader of the newspapers and may have took this bait of using a publication by Edgar Allan Poe, thinking he was getting one over on Dr Marsh and the police. The hope from the standpoint of law enforcement, was that the Zodiac Killer would bite the hook and get reeled in. 

Sixteen days later the Zodiac Killer mailed the 340 cipher revealing, not his name, but his identity, carefully positioned at the base of his cipher. This catapulted the idea that the Zodiac Killer had indeed responded to the article by Dr Marsh, but wasn't quite ready to reveal his name to authorities. But it is my belief that the Zodiac Killer did create the 340 and 13 Symbol ciphers in tandem, with a view to inextricably link his identity to his name using the word "Zodiac" on the final row of the 340 cipher, with the three 8's as the conduit between the two. See here.

The Zodiac Killer, however, would hold back his '13 Symbol' cipher for approximately six months. Zodiac researcher Michael Cole stated "Clearly, the Zodiac did not send the cryptogram to Marsh, as had been requested (this non-public way of satisfying the challenge was apparently unacceptable to the attention-craving serial killer). Neither did he respond in a time frame that most would have expected. But these details matter little. In fact, the timing itself provides yet another reason to conclude that what we have here is a specific instance of cause and effect. As mentioned, this article was published in the Examiner on October 22, 1969.  Six months to the day later, April 22, 1970, the people of the San Francisco Bay Area were reading about the My Name Is cipher in the Chronicle."

But there may have been a much more cunning reason why the Zodiac Killer delayed his mailing of the April 20th 1970 communication, and it has everything to do with Edgar Allan Poe. Did the Zodiac Killer pick up on the wording of Dr. D.C.B. Marsh in the article, create and mail his '13 Symbol' cipher based on something in the writings of Edgar Allen Poe? 

We can see in the Edgar Allan Poe essay 'A Few Words on Secret Writing,' at the very beginning he shows the alphabet being split into two halves of 13 letters, A to M, and N to Z.
"Were two individuals, totally unpractised in cryptography, desirous of holding by letter a correspondence which should be unintelligible to all but themselves, it is most probable that they would at once think of a peculiar alphabet, to which each should have a key. At first it would, perhaps, be arranged that a should stand for z, b for y, c for x, d for w, &c. &c.; that is to say, the order of the letters would be reversed. Upon second thoughts, this arrangement appearing too obvious, a more complex mode would be adopted. The first thirteen letters might be written beneath the last thirteen, thus:
n o p q r s t u v w x y z
a b c d e f g h i j k I m; and, so placed, a might stand for n and n for a, o for b and b for a, &c. &c. This, again, having an air of regularity which might be fathomed, the key alphabet might be constructed absolutely at random." ​​

The Zodiac Killer not only created the April 20th 1970 cipher with 13 characters, but it too began with an A and ended with an M, just like the suggested encryption technique featured by Edgar Allan Poe. Notice the way the cipher is organized symmetrically using the alphabetical characters, the three 8's and the two symbols. The same symmetry was observed when placing half the alphabet alongside the 13 character cipher. See here.  

The Dr. Marsh newspaper article opened with "A Challenge perhaps unique in the annals of American crime was injected today into the bizarre case of the killer who begins his letters to newspapers 'This is the Zodiac Speaking'."
The article continued, and bemoaned the fact that Zodiac hadn't revealed his true identity: "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." 

'A Few Words on Secret Writing' stated "This challenge has elicited but a single response, which is embraced in the following letter. The only quarrel we have with the epistle, is that its writer has declined giving us his name in full. We beg that he will take an early opportunity of doing this, and thus relieve us of the chance of that suspicion which was attached to the cryptography of the weekly journal above-mentioned–the suspicion of inditing ciphers to ourselves. The postmark of the letter is Stonington, Conn." ​link. 

If the Zodiac Killer was basing the '13 Symbol' cipher on the Dr. Marsh article and secret writing of Edgar Allan Poe, why did he wait approximately six months to mail it to the San Francisco Chronicle?
It may not have been the six month anniversary that was important to him, but the only date mentioned in the Edgar Allan Poe literature, 'A Few Words on Secret Writing'. The date was April 21st. 
Had the Zodiac Killer deliberately waited six months to ensure his '13 Symbol' cipher letter would be postmarked April 21st, or be published on April 21st, which unfortunately for him never materialized? He was slightly early on the mailing, resulting in the postmark of April 20th, and the San Francisco Chronicle published his cipher in the April 22nd edition, effectively thwarting any intentions to recreate the Connecticut letter.

However, the possibility remains, that the Zodiac Killer could have used one of the cipher techniques employed or suggested by Edgar Allan Poe in 'A Few Words on Secret Writing', and the idea proposed by 'Nobody' regarding the use of a second language as the key, a much more viable proposition than initially considered.
​
 "It is not to be supposed that Cryptography, as a serious thing, as the means of imparting important information, has gone out of use at the present day. It is still commonly practised in diplomacy; and there are individuals, even now, holding office in the eye of various foreign governments, whose real business is that of deciphering. We have already said that a peculiar mental action is called into play in the solution of cryptographical problems, at least in those of the higher order. Good cryptographists are rare indeed; and thus their services, although seldom required, are necessarily well requited. An instance of the modern employment cipher is mentioned in a work lately published by Messieurs Lea & Blanchard, of this city–“Sketches of Conspicuous Living Characters of France.” In a notice of Berryer, it is said that a letter being addressed by the Duchess de Berri to the legitimists of Paris, to inform them of her arrival, it was accompanied by a long note in cipher, the key of which she had forgotten to give. “The penetrating mind of Berrver,” says the biographer, “soon discovered it. It was this phrase substituted for the twenty-four letters of the alphabet–Le,gouvernement provisoire.” 'A Few Words on Secret Writing' by Edgar Allan Poe.

In a recent article David Oranchak posed the question "Are the Ciphers Gibberish", analyzing the pros and cons to the legitimacy of the Zodiac 340 cipher. There is, however, another legitimate argument to be discussed when searching for a solution to the Zodiac Killer's second cipher. Is it worth trying to solve at all? If it does contain a message, it will likely be a collection of inane ramblings akin to the solved 408 cipher. There will of course be the immense notoriety attached to your name, having been the cryptographer who broke the infamous Zodiac code, from which numerous television appearances and a book deal will inevitably follow. In the midst of tragedy, your name will be up in lights. But here is the reality check. Even if you do achieve the seemingly insurmountable task of unequivocally solving the 340 cipher, then comes the next insurmountable hurdle - convincing people you have the correct solution. In a Zodiac community wearily grazing on skepticism and fueled by a heavy dose of déjà vu syndrome, your perfectly good solution will likely drift on down the river with barely a ripple from the esteemed adjudicators.   

Even if it does get snagged by an overhanging branch for a fleeting moment, attempting to prove that the "key" used to decipher it, is the one Zodiac intended, will again create a hill you can never climb.

There are so many claimed solutions to the 340 cipher haystack, that if one really existed, it will eventually be as hard to find as a solution to the cipher itself. David Oranchak stated here:   
​"The 340 cipher has 63 unique symbols. If one of 26 plaintext letters can be assigned to each symbol, then the number of possible solutions is 26 raised to the 63rd power. So, how many of those solutions would computers need to examine PER SECOND to finish within 100 years? The answer is about 4.4 x 10^80 solutions, or 440 million billion billion billion billion billion billion billion billion. This is LIGHT YEARS beyond what current computers are capable of.
According to Top500.org, the world's fastest supercomputer as of November, 2011, achieved a computational power of 10.51 Petaflop/s, or 10.51 quadrillion floating point operations per second. If you were somehow able to check a decryption solution of the 340 cipher using a single floating point operation, then this supercomputer could go through all of the possible solutions to the 340 cipher in about 1.3×10^57 years. By comparison, our humble universe is estimated to be only 13.7 x 10^9 years old!"

With so many variables that can be applied to the cipher, or more importantly, the one conjured up by the warped and dissociative brain of Zodiac, the probability is, that a supercomputer designed by logic and born from reality will probably be heading course on the wrong superhighway. Throw in a handful of Zodiac errors into the mix, could mean proving your solution an impossible task to the baying hordes of furrowed experts, armed with statistical probabilities. Solving the 340 cipher may yet prove to be the easy part, however, convincing somebody else you have, could take a quadrillion years you haven't got.

David Oranchak stated "When Z408 was cracked, the papers talked about how the solvers took advantage of patterns found in the cipher text. Zodiac could have focused on somehow removing those patterns from Z340. Or maybe he found some obscure idea in a book or one of those pulp fiction detective stories".
​Herein lies part of the problem. If you discover an obscure idea that answers key elements of the 340 cipher, or provides a readable message (possibly using a rotating key code), then it could be argued that your obscure idea is so obscure, that it isn't worth considering as a credible solution and thereby roundly dismissed as lunacy. The more crazy the solution, the more unlikely it is, despite being crafted by the perfectly sane Zodiac.

Alternatively, how do you prove the cipher gibberish while it still remains unsolved in the eyes of most observers. By extension, if it's unsolved, then it still has a possible solution. But be warned - if you do find the real solution to the 340 cipher, you will have to work far harder than the Harden's did in 1969 to convince the world you are correct. And my guess is, you never will.