Zodiac 340 Cipher Solution

Zodiac
        Killer 340 Cipher

In 2012, after watching the movie, "Zodiac", I began toying with the 340 cipher, and came to what I felt was 90-95% of the solution. (Please see the 2012 solution Image and 2020 proposed full solution links at the end of this document.) Note that for working ease, I assigned a number to each cipher character and that there were 'leftovers' when it came to uncovering words towards the end of my 2012 solution (33 ,39, 40, 61). Those numbers have been assigned letters in the 2020 solution.  If you are not familiar with the Zodiac case, please see these important links.

    To simplify things for now in a nutshell:

the cipher is, ironically, an encrypted word-search with strong allusions to the killer's identity and, as the FBI thought, a major message contained near the middle of it. The message clearly shows it's a word search: “Hoot at the Halloween. Circle the words to seeh the helot hell.”  ('Circle the words' is the crucial part. Please note: more about how the decoding was done is here. For now suffice it to say, I used letter frequency and a home-spun little computer app as a solution aid.).


     A couple of interesting things to note about the main message are:  the term, 'helot' suggests a familiarity with military history and humans as game (in keeping with the 408 reference to "The Most Dangerous Game"). Furthermore, the main message foreshadows the Zodiac Killer's Halloween card sent the next year to the San Francisco Chronicle, on October 27th 1970.

[Aug 8/20: There is also a major message with regard to the Zodiac's symbol. If we consider the 'O' before 'Logic' to be a zero, then we can make the sentence, "End the 0 (zero) logic", which nicely explains the Zodiac's symbol of a circle with a cross through it.) With 'Leroi' (Le Roi) circled as well, that 'O' is at the center of a word cross.


    Once decoded, in addition to a variety of ominous and other words (like 'roast', suggesting his bomb threat, and later threat of killing 'by fire'), we often see the name 'LEE' (5 times, 7 if 33 is 'E'), and at one particular part (over 14 squares and down 15, and then reading upwards) what appears to be the Zodiac toying with the full name, Arthur 'Lee' Allen. Although not all letters are present for the full name, we see A, then 39 (possibly 39 is also 'T'), H, R, then Lee, and then ALL. That is, ATHR LEE ALL, which in a word-search context nicely alludes to the Zodiac's real identity, without fully naming him. That said, in conjunction with the frequency of LEE, the circumstantial evidence starts to look more than appetizing.(See Image below: please note I've circled every word on paper copies, but the image here doesn't show all words discovered in the search.) Similarly, in the upper left quad, is 'ALEEN', which contains, LEE, while suggesting ALLEN as well. Likewise, moving upwards from the A of 'AT' in the main message, is AELLN, which also suggests ALLEN. (Toying with the name ALLEN may also be something the Zodiac did with the indecipherable, "My name is _" cipher, as it begins with AEN....possibly to suggest Allen, without the 'L'. It's interesting, that if you turn the line after "My name is" upright...you get a lowercase 'l'. He could have used a colon or comma at that part. Perhaps that's pushing it just a little, but maybe not.)

    In the word-search we see the Zodiac possibly thinks of himself as 'sly', 'wise' (like a Halloween owl) 'coy' and 'wry'. (The way 'coy', 'wry' and other related words intersect suggests design, as does the use of related words like 'halloween', 'owl' and 'wise' within the same word-search.) He uses logic (but may be 'theologic'al: hence the outfit he wore). As well, possibly in accordance with a murders-near-water theme, we see 'Chlorine' (circled) and "Pool' (also 'Loop' - using the 'o' in 'helot'). Of course, chlorine may also be a reference to deadly gas.

    [Some speculation: In the word-search are three instances of 'Leo', perhaps suggesting Lee thinking of himself as 'King of the Zodiac'. Not beyond reason, but perhaps weighty in conjecture; or maybe not. If '33' is 'E' then 'Sire' intersects with 'Leroi' (Le Roi = The King, in French) near the top. Also, the proximity of 'kill', 'sire' and 'leroi' conjure up notions of the prior Martin Luther King assassination....Is the Zodiac implying something here, or trying to take credit? Interestingly, around the zero 'O' in the 'zodiac symbol message' is 'erl, le, i, he' (from left to right), which could be some kind of phonetic statement. Is this perhaps an earlier cipher than the 408, but submitted later? Or was he thinking of someone else known as, 'The King'? Regardless, the notion of 'king' definitely appears in the search. In fact, if you use 'ing' triplets to solve this, one dead-end leads to some instances of 'king' in the solution, almost as if the Zodiac knew that would be the case.]


    Near the section that suggests the entire name, and near two instances of Lee (using part of one Lee), is also the name 'el rey' (on a diagonal). I can't recall for sure if this name has special importance (I'm returning to this after 8+ years), but think I've read/heard it's a place, restaurant or tavern connected to one of the victims. If so, given the proximity of words together, it seems as if it were carefully crafted to suggest Lee at the scene of el rey. (This is similar to how the creator of the word search places owl in relation to the main, "Hoot at...." message.)


    I was in public school at the time of the Zodiac killings, and word-searches were starting to become very popular in newspapers. Therefore, I believe he drew on this, perhaps due to his relationship with the San Francisco Chronicle. It seems as if 'circle the words' (or something longer like, 'circle the words to hoot at the hallloween owl') is possibly a segment of a common word-search's outer instructions, embedded into the search itself. It's possible the Zodiac reworked a search that had been in a recent paper at that time.  I haven't checked this, but that would be very strong evidence if discovered.


    Since Arthur Leigh Allen (commonly know as 'Lee'), did not become a suspect until after the cipher was presented, we must wonder why the high frequency of the name Lee and such a strong allusion to Arthur Leigh Allen are present in the 340.

    By encoding a word-search into a cipher, the Zodiac was able to tell us something about himself, allude to his identity, yet remain illusive.  Fifty years down the road even writing about the 340, after solving it, presents some very convoluted challenges.

Main Solution Image

main solution image

Here's a link to an unmarked image of the 2012 solution in the app.

Here's a link to an image of a proposed full 2020 solution. (with 33 and 40 = 'E', 39 = 'T', and 61 = 'X')

Here's a link to an image of the proposed full 2020 solution with many sections circled.

Copyright © 2012-2020 by R. Grant Davis    contact:   eeporuk@hotmail.com