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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

The Zodiac Killer's primary focus was attention from the media, who themselves also benefited from the extensive reporting of his murderous campaign, letter writing and extortion, in a form of symbiotic relationship. The murderer would use this to full advantage during and after his confirmed attacks dried up, often claiming or insinuating his involvement in certain crimes. The August 1969 Debra Gaye Furlong and Kathie Ann Snoozy stabbings, along with the 1970 murders of Robert Michael Salem, Officer Richard Radetich and Donna Ann Lass come to mind. But the killer was also prepared to mention other crimes, such as the murder of San Francisco police officer Brian McDonnell on February 16th 1970: "I hope you do not think that I was the one who wiped out that blue meannie with a bomb at the cop station.  Even though I talked about killing school children with one. It just wouldn't doo to move in on someone else's teritory.  But there is more glory in killing a cop than a cid because a cop can shoot back." The Zodiac Killer wasn't averse to rubbing their "noze in their booboos" when adversity came their way.
The following is extremely speculative and probably way off base, but since it has never been suggested before (as far as I am aware), it is worth putting forward as a possible example of Zodiac piggybacking a crime unrelated to his murderous exploits. 

At approximately 8:10 pm on October 19th 1970 Lieutenant Shaw and Sergeant Noren entered the Sosquel area of Santa Cruz, California responding to a fire on a hill between Rodeo Gulch Road and San Jose Road. The horror of what ultimately lay at 999 North Rodeo Gulch Road was yet to be unearthed.

The bodies of Dr. Victor Ohta (45) and his wife, Virginia (43), along with their two sons, Victor Taggart (11) and Richard Derrick (12), and secretary, Mrs Dorothy Cadwallader (38) were found murdered in the swimming pool of the residence. They had been callously executed.

Dr. Ohta had been shot in the back and under the arm, while the others had been shot in the back of the neck. It was literally a bloodbath. The victims had been bound and blindfolded with scarves before being murdered. The Ohta residence was then set on fire. When the fire crews arrived at the isolated estate they were hampered by Dr. Victor Ohta's Rolls Royce and Mrs. Dorothy Cadwallader's Lincoln Continental blocking the entrance.

Later that day Dr. Ohta's green Oldsmobile station wagon was discovered burnt out on railway tracks near Felton, approximately 18 miles northwest of the crime scene. Although not definitively linked to the other five murders, Thomas DeCecco (19), a service station attendant was found bound and shot in the head near Saratoga only hours after the initial crime, possibly bringing the victim count to six.    

"KPIX News footage from October 20th 1970 with reporter Pat O'Brien featuring scenes from a house in Soquel, CA, in the aftermath of the mass murder of eye surgeon Dr. Victor Ohta, his wife Virginia, two sons Taggart and Derrick and secretary Dorothy Cadwallader. Includes aerial views of the Ohta home, the swimming pool in which their bodies were found." link.

A typewritten note was discovered under the windshield wipers of Dr. Ohta's Rolls Royce. It stated "Halloween...1970. Today World War III will begin as brought to you by the people of the free universe. I and my comrades from this day forth will fight until death for freedom, against anything or anyone who does not support natural life on this planet. Materialism must die or mankind will." Signed "Knight of Wands, Knight of Cups, Knight of Pentacles, Knight of Swords."

John Linley Frazier was arrested shortly after the murders and was sentenced to death on November 29, 1971. However, in 1972 the death penalty was abolished in California and his sentence was commuted to life imprisonment. He committed suicide by hanging  on August 13th 2009.

One week after the Ohta murders and typewritten note stating "Halloween...1970", the Zodiac Killer mailed the 'Halloween' card on October 27th 1970, featuring two skeletons, with twelve eyes added to its design. One eye peered from the knothole of a tree, surrounded by the words "peek-a-boo you are doomed". Why did the killer add twelve eyes to this card?
​Dr. Victor Ohta was an eye surgeon (ophthalmologist), and six possible victims were reported in the newspapers (6 pairs of eyes). The skeletons on the card outer and inner also had the eyes highlighted in red, one in the form of a blindfold, in similar fashion to the victims thrown into the pool. 

Zodiac researcher Tom Voigt 'floated' this idea on his message board in 2012: "I received an interesting observation of the Halloween card via e-mail recently -- it suggested the skeletons were meant to depict a water scenario, with the top skeleton being a diver (my guess would be the pumpkin representing swim trunks?) and the bottom skeleton floating under water, I'm guessing then the many eyes possibly representing bubbles?" What if the water was from the swimming pool at 999 North Rodeo Gulch Road.

The 'Halloween' card would emphasize four methods of death: By Fire, By Gun, By Rope and By Knife, three of which would feature heavily in the Ohta murders.

Had the Zodiac Killer read the coverage of the brutal murders at Sosquel and beyond, and fearing that his relevance was dwindling in the newspapers, used the crime of John Linley Frazier to piggyback himself back into prominence? If this was the case, unfortunately for him, nobody understood the connection, and the meaning of the 'Halloween' card was lost in translation. As an explanation for the October 27th 1970 correspondence, this is probably wide of the mark. It does, however, give us a flavor of some of the radical views that permeated California in the 1960s and 1970s, and the beginning of the end for the Zodiac Killer.

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

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

On December 30th 2013 Tahoe27 gave us the 'Wheel of Death' from the Tim Holt comic book. It contained a Rota Fortunae style game in which 'Redmask' would discover his fate based upon twelve methods of death.
​The Zodiac Killer appeared to be inspired by the comic, either before or after his canonical crimes began on December 20th 1968, writing the words "by knife" on the car door of Bryan Hartnell's 1956 white Volkswagen Karmann Ghia. He may have hinted towards this comic when designing a crude code and drawing on the Fairfield letter, mailed on December 16th 1969. However, on October 27th 1970 the 'Halloween' card contained a design depicting four methods of death, all of which mirrored the cover of the Tim Holt comic book.
In total, the twelve methods of death ran around a Zodiac styled wheel: "In medieval and ancient philosophy the Wheel of Fortune, or Rota Fortunae, is a symbol of the capricious nature of Fate. The wheel belongs to the goddess Fortuna (Greek equivalent Tyche) who spins it at random, changing the positions of those on the wheel: some suffer great misfortune, others gain windfalls. Fortune appears on all paintings as a woman, sometimes blindfolded, "puppeteering" a wheel. The origin of the word is from the "wheel of fortune" - the zodiac, referring to the Celestial spheres of which the 8th holds the stars, and the 9th is where the signs of the zodiac are placed."
Nevertheless, the Zodiac Killer only chose four- death By Gun, By Rope, By Knife and By Fire. He also added a strange symbol to the card that has perplexed many an observer over the years - a symbol that has prompted many suggestions, including cattle branding, a depiction of Mount Diablo and a form of victim running total.
The symbol may possibly be a joined Z and F, indicating that Zodiac is claiming fourteen victims, or maybe a joined Z, V and F symbolizing Zodiac Victims Fourteen. However, the four dots accompanying the symbol have always been difficult to explain with any degree of confidence. We have four methods of death chosen by Zodiac, therefore the possibility exists that the four dots are somehow related. What we may be looking for, could be Zodiac Victims Fourteen By Gun, By Rope, By Knife and By Fire. The Zodiac Killer in all likelihood drew inspiration for his 'methods of death'/Paradice and Slaves configuration from the Tim Holt comic book, so why should the strange symbol be any different.        

If we superimpose the strange symbol Zodiac designed over the four 'methods of death' on the wheel of the Tim Holt comic book, the four dots land squarely over the four prescribed methods of death. 

There is no definitive evidence to totally negate the idea that the 340 cipher contains a viable solution- with the mystery and allure of the Zodiac Killer code the driving force behind people wishing it were genuine. This, of course, exempts the 500+ people who have already solved the 340 cipher, in solutions now extending longer than the Bayeux Tapestry.  
Obviously, Zodiac researchers who specialize in the ciphers rather than the crimes themselves, have a vested interest in wishing the cipher to be a hidden message. This is the belief that keeps the dream alive.
But did the Zodiac Killer really have the ability to create a more difficult cipher than the 408, with a reasonable expectation of a solution. Placing 29 unique characters into a 32 symbol cipher, and creating a 13 symbol code would suggest not.
The October 22nd 1969 Examiner newspaper article by Will Stevens, laid down a challenge to the Zodiac Killer from the president of the American Cryptogram Association (ACA), Professor D.C.B. Marsh, to reveal his name. This may be the article that inspired the 340 cipher, and by association, the 'Halloween' card mailed approximately one year later.
 "Dr Marsh told the Examiner today: "The killer wouldn't dare, as he claimed in letters to the newspapers, to reveal his name in the cipher to established cryptogram experts. He knows, to quote Edgar Allen Poe, that any cipher created by man can be solved by man. Zodiac has not told the truth in his cipher messages to the Examiner, the Chronicle and the Vallejo Times-Herald. Zodiac has not done this, because to tell the complete truth in relation to his name-in cipher code-would lead to his capture. I invite Zodiac to send The American Cryptogram Association a cipher code, which will truly and honestly include his name."
This contention is probably true- that the Zodiac Killer wouldn't reveal his name in any cipher (other than his pseudonym), and additionally, he likely used the fact "that any cipher created by man can be solved by man" as a springboard to create something extra special, other than a cipher. If we contend that the Zodiac Killer wrote his final letters in 1974, then is it likely that a killer touted as an attention seeker, could resist dropping us clues to the 340 cipher in his subsequent letters, spanning in excess of four years. 
Each and every one of his final three communications in late 1970 and early 1971 effectively told us he was crackproof. The upside down text on the October 5th 1970 'Pace' card stated "Fk I'm crackproof." The October 27th 1970 'Halloween' card proclaimed "sorry no cipher." The March 13th 1971 'Los Angeles' letter boasted "Like I have allways said, I am crack proof." But the Zodiac Killer hadn't always said he was crackproof- only in the two communications either side of the 'Halloween' card announcing "sorry no cipher." The suggestion he was crackproof, thereby not arising from his perceived ability to evade police, but from his smugness in knowing he created three ciphers he knew would never be solved. 

The Tim Holt comic find by Tahoe27 in 2013, and the recent assertion of a close alliance, not only with the 'Halloween' card, but the 340 cipher, has been covered here to reject the 340 cipher as containing a viable and coherent message.
In view of the "by knife" attribution on Bryan Hartnell's car door, it is arguable that the Zodiac Killer had the Tim Holt comic book or Rota Fortunae (Wheel of Death) in mind as he wrote on the car door. In other words, the concept predated the September 27th 1969 Lake Berryessa stabbings, rather than just the 'Halloween' card. The Lake Berryessa "by knife" attribution becoming the part inspiration for the complex puzzle of the 340 cipher.
The "by knife" method of death (on the right) is clearly the only one falling within its quadrant, as opposed to the others, which are all connecting with the central column.
This method of death was certainly prioritized by the Zodiac Killer, having placed it on Bryan Hartnell's vehicle (despite the fact the crime was obviously committed with a knife). The feasible presence of "by knife" within the 340 cipher. The possibility of a crude 'Halloween' card design in the December 16th 1969 'Fairfield' letter featuring "death by knife," along with the "Bleeding Knife of Zodiac" drawing. And finally, the 'October 27th 1970 'Halloween' card design and comic book, both containing "by knife" and mirroring the 340 cipher and 'Fairfield' letter.
Below are the speculative beginnings, attempting to interweave the '13 Hole' postcard into the emerging design. 

This is the last time this subject will be tackled for the foreseeable future, unless something magical sticks its head above the parapet- but before that happens- there is just one more addition to the idea of an extremely close alliance between the 'Halloween' card and 340 cipher, and the suggestion that the 340 cipher is not a meaningful and coherent message by the Zodiac Killer.
Just about every feature of the October 27th 1970 'Halloween' card, including the envelope and stamp, can be shown to exist within the 340 cipher, making the December 2013 discovery by Tahoe27, of a Tim Holt comic book connection, all the more compelling. Her discovery may have opened the door to finally end the debate on the validity of the 340 masterpiece, and place the pseudonym 'Zodiac' front and center to the 'Death Wheel' featured on the comic book cover.
At what juncture the Zodiac first stumbled across his pseudonym is of little importance, however, it could be argued that when he found it, he would likely research the name 'Zodiac' and use elements of his research to incorporate into his future correspondence. If he had happened upon the Tim Holt 'Death Wheel' comic prior to November 8th 1969, then the light bulb may have switched on, and his design of a crackproof cipher began in earnest. And possibly, a 340 cipher designed in tandem with the Tim Holt comic and cipher three, which he mailed just over five months later on April 20th 1970. His opening line of "This is the Zodiac speaking. By the way have you cracked the last cipher I sent you. My name is....", he may have already known the answer to when he manufactured the illusion of a 340 character message.        

Here is a brief recap before we move on.
The 'Halloween' card stamp contained 17 letters "In the beginning God" that slotted nicely onto the first line of the 340 cipher, with characters 15,16 and 17 awkwardly similar- including the half-earth image present on the stamp.
Paradice and Slaves can be shown as a distinct possibility, bisecting the 340 cipher horizontally and vertically, just like the 'Halloween' card arrangement. Seventeen characters horizontally and vertically in either direction, to create the perfect crosshairs of Zodiac.
The word "by" can be found in all four quadrants of the 340 cipher, mirroring the 'Halloween' card arrangement.
At least seven, possibly eight characters on the 14th line of the 340 cipher can be formed into the design of the 'Halloween' card inner. Explanation here. 
"Sorry no cipher" written on the envelope inner and designed in similar fashion to Paradice and Slaves arrangement on both the 'Halloween' card and 340 cipher, explicitly instructed us that no cipher existed on November 8th 1969.
One has to presume that all these fell here by accident (including the inference to Zodiac on the 20th line), because to believe otherwise, would pour huge doubt on a Zodiac Killer who was able to simultaneously create a uniform message within the 340 cipher in conjunction with a 'bag of puzzles'. 
However, the Tim Holt 'Death Wheel' comic is not only interesting because it contains By Fire, By Gun, By Rope and By Knife, found in the 'Halloween' card, or because of "Redmask" or "Lady Doom," but because of the origin of the 'Death Wheel' or 'Wheel of Fortune' itself. 
Had the Zodiac Killer read anything about the pseudonym 'Zodiac' when he first appropriated it, then he may have known the relevance of the 'Wheel of Fortune' or 'Rota Fortunae,'. thereby triggering the inspiration for the 340 cipher, and the eventual 'Halloween' card explanation or solution to his devilish trick and treat.          

We could just assume that when the Zodiac Killer spotted the Tim Holt 'Death Wheel' comic book, he liked the fact it represented some or all of his killing methods, and simply chose it because of its menacing touch. However, he may have chosen it because of the pseudonym he had grown so attached to- a pseudonym he would seemingly place at the foot of the 340 cipher.
The 'Wheel of Fortune' or 'Rota Fortunae' has a long and rich history, crossing many cultures and eras. Here is an excerpt from Wikipedia:
"In medieval and ancient philosophy the Wheel of Fortune, or Rota Fortunae, is a symbol of the capricious nature of Fate. The wheel belongs to the goddess Fortuna (Greek equivalent Tyche) who spins it at random, changing the positions of those on the wheel: some suffer great misfortune, others gain windfalls. Fortune appears on all paintings as a woman, sometimes blindfolded, "puppeteering" a wheel."
The great windfall may be the promise of paradise, but the downside is the servile nature expected by the one who summoned you.
But here is the interesting part- again taken from Wikipedia. 
"The origin of the word is from the "wheel of fortune" - the zodiac, referring to the Celestial spheres of which the 8th holds the stars, and the 9th is where the signs of the zodiac are placed. The concept was first invented in Babylon and later developed by the ancient Greeks. The concept somewhat resembles the Bhavacakra, or Wheel of Becoming, depicted throughout Ancient Indian art and literature, except that the earliest conceptions in the Roman and Greek world involve not a two-dimensional wheel but a three-dimensional sphere, a metaphor for the world. It was widely used in the Ptolemaic perception of the universe as the zodiac being a wheel with its "signs" constantly turning throughout the year and having effect on the world's fate (or fortune)." link.
The zodiac is an area of the sky that extends approximately 8° north or south (as measured in celestial latitude) of the ecliptic, the apparent path of the Sun across the celestial sphere over the course of the year. The paths of the Moon and visible planets are also within the belt of the zodiac. The Zodiac is divided into 12 signs beginning with Aries and Taurus.
The Zodiac wheels have multiple cultural adaptations, shown here in a Wordpress blog:
"These zodiac/time wheels are not common in Eastern Orthodox iconography, but they are found in one variation or another occasionally — usually, as here — in the form of wall paintings in churches. When seeing such a “Wheel of Time” — also called a Wheel of Life — one cannot help thinking of those Tibetan images that also represent a wheel of life as the “Wheel of Becoming” — in this case a wheel of rebirth:"
Here is one final extract from the book 'Deep Value:
Plutarch says that Servius knew "fortune is of great moment, or rather, she is everything in human affairs" because it was through good fortune that he had ascended from slave to king. In Roman mythology Fortuna was the goddess of fate, and the personification of chance. She turned the Rota Fortunae- the Wheel of Fortune- which dictated the destiny of man." Therefore, did Zodiac dictate the destiny of his victims-  By Fire, By Gun, By Rope and By Knife- the very reason the 'Wheel of Death' portrayed on the Tim Holt comic was so very appealing.

The discovery by Tahoe27 linking the Tim Holt comic was fascinating in so many ways, yet, it may not have been the inspiration behind the 'Halloween' card, but the inspiration behind the 340 cipher and its accompaniment- the '13 Symbol' cipher.
If the Zodiac Killer had done his research and discovered the 'Wheel of Fortune' or 'Rota Fortunae', and its connection to the word 'Zodiac', then the Tim Holt comic may have been a gift from heaven- an offering he just couldn't resist. 
Five weeks after the November 8th 1969 340 cipher, the December 16th 1969 'Fairfield' letter may have shown the early machinations of the Zodiac design, appearing in rudimentary code- the full explanation of which would have to wait until October 27th 1970..
The interconnectivity between the 'Halloween' card, Tim Holt 'Death Wheel' comic, the pseudonym 'Zodiac' and the 340 cipher is an intriguing and perplexing blend of mystery. One that came together by deliberate intent, or came together from the mind of somebody wishing it were true.