OK, I’m going to start this post by embedding S01E03 of the History Channel’s “The Hunt for the Zodiac Killer”, because this is what started me on the road to the solution to the Donna Lass cipher:

About half the episode is taken up with trying to make links between the Zodiac Killer and Donna Lass’s disappearance in 1970, a connection for which there seem to be two primary pieces of evidence – a poster (with a cryptogram) and a postcard. However, as we’ll see, it turns out that there are serious problems here which the series makers chose to fast-forward their audience past.

Who Was Donna Lass?

According to her FindAGrave website entry:

Donna was the daughter of James and Frances (Kukar) Lass. During high school, her activities included F.H.A. and singing in mixed chorus. During her senior interview, she stated that her plans were “to go college or be a nurse.” She was one the fifty-two members of the graduating class of 1962 at Beresford High School in Beresford, South Dakota.

Donna was listed as a survivor in the 1973 obituary of her father; but, she was listed as deceased in the 1982 obituary of her mother.

It’s hard not to conclude that hope for her survival died with her mother.

There are some reasonably good pictures of her on the Internet:

What happened to her? According to the official missing person’s page that discusses her:

Donna Lass was last seen in South Lake Tahoe, she left her residence without her vehicle or personal belongings. Lass worked as a nurse at the “Sahara Hotel-Casino”. Her last entry in the nurse’s log book was at 1:50 a.m., and although her car was found parked at her apartment complex in nearby Stateline, she wasn’t seen after leaving the Sahara.

The next day, an unknown male called her landlord and employer, stating Lass wouldn’t be returning due to a family emergency. The call was a hoax, and there has been no trace of Lass ever since

Of course, none of this sounds remotely like the Zodiac Killer’s modus operandi: so you’d have thought there really ought to be some good evidence out there linking the two, given the longevity of these claims.

The Donna Lass Cipher

The cipher first appeared on a reward-for-information poster, with each cipher shape underlined by hand. It’s unclear to me whether the underlining was originally designed in to the poster, or whether it was added by hand to the poster in the only genuine copy of the poster we have.

In episode S01E03 of “The Hunt for the Zodiac Killer”, the editing makes it seems as though everyone spends some time following a – frankly somewhat pathetic – interpretative anagram of the above cipher, that magically turns the cryptogram into driving instructions to get to some woods that just happen to have a TV-friendly creepy historical backstory (the Donner Pass cannibalism story, yada yada yada). In my opinion, this is right up there with people who draw pencil lines between similar letters and then try to convince you that it is not the cryptogram itself but rather those pencil lines that are the ‘real’ treasure map. *sigh*

Moreover, it was immediately clear to me (as I’m sure it was to everyone in the codebreaking team) that this particular reading wasn’t even close to being close: and, moreover, that the patterns of shapes were more or less exactly as you would expect a simple substitution cipher to present (for instance, the presence of doubled letters pointed directly away from any thought of Zodiac Killer-style homophones).

So once I’d got to the end of the programme, I found a copy of the cipher online and wrote it down on a piece of paper. Within ten seconds, I realized that the last set of shapes could only sensibly be DONNALASS: and that gave me enough letters to get to STALKING, and within a few minutes I also figured out that the larger phrase was I AM STALKING.

The next morning, when I ran a test to find words that fitted the pattern of the first six letters, only two words fitted – BEHAVE and BEWARE. Eliminating BEHAVE gave a nearly-complete decryption:


I then immediately felt a bit of a fool that I hadn’t immediately noticed that this was exactly the same as the start of the last sentence of the Riverside “Confession” letter: “BEWARE . . . I AM STALKING YOUR GIRLS NOW” (there’s a copy here):

After a little more thought, I became convinced that the first of the two outline triangle shapes at the start of the second line should probably have been an upside-down outline triangle, and that the original plaintext for the Donna Lass cipher was (without any real doubt):


Put all this together, and you’d have to say this looks like a cryptographic slam-dunk to link the crime to the Zodiac Killer’s “The Confession” letter (even if – in my opinion – he probably only tried to take ‘credit’ for Cheri Jo Bates’ murder, i.e. he didn’t do it himself). You can even see how the cipher shapes were laid out in a 5 x 5 grid by the encipherer, because the triangle shapes are all five letters apart, as are all the backwards letters.

However, it turns out that even though this is definitely the correct plaintext for this cryptogram, there are a number of issues

The Donna Lass Poster

The full poster looks like this:

For a start, it turns out that I was reinventing the wheel here (as far as solving this cipher goes). A number of other people had worked out the exact same plaintext a decade or more earlier than me – the earliest mention I found was May 2007: but given that it was so straightforward, it would be unsurprising if yet others had solved it long before then.

Problematically, commenter Seagull pointed out that:

The reward poster for Donna Lass, that Tahoe27 linked, can’t be from the ’70’s because the Area Code for the phone number did not come into being until 1997. […] Maybe this reward poster is from the time of Harvey Hines investigation.

Even Wikipedia lists this fact: “Created in 1997 by split from 916.” From that alone, there seems no chance at all that this poster was really from 1970 or 1971.

Moreover, commenter Slug then quickly pointed out (a) that the typesetting seemed inconsistent with the 1970s, and (b) that it seemed to have been laid out in close-to-exactly the same way that MS Word 97 would have done it. Others have also pointed out that it used Times New Roman, further compounding the period inaccuracy of the thing.

Finally, commenter Jupiter noted “a newspaper article about the Lass murder, written in 1971, that details a $500 reward put up by the family and people with information were to contact a private eye hired by the Lass family. There is no mention of having people contact the police with the info and the reward is considerably smaller”.

So where did the poster come from? Tom Voigt got it from Howard Davis, who in turn said:

Donna’s sister Mary sent that poster to me.It was done by the Lass family.

When asked about it, he then went on:

Mary mentioned to me a few times they had a family member(or in law) that is into computers,graphics,etc. He may have done the poster. She told me the reward was no longer in effect as I recall.Note at the bottom of the poster the family is mentioned.I do hope this doesn’t go into a all out contraversy as it was just an attempt at the time by the family to seek more information.I have enough to do as it is.Remember that Hines had pretty much convinced them Kane was the perp,hence,the ‘positive’poster wordage about having information,etc.

Put all this together, and the picture that finally emerges seems to be of the Zodiac theory industry collectively manufacturing a connection between Donna Lass and the Zodiac Killer – that is, Zodiac theorists convincing Hines so strongly that Laurence Kane (who Donna Lass personally knew) was the Zodiac Killer that he incited the Lass family to include a fake Zodiac-style cryptogram on a later faked-up poster.

The awful (and stupid) thing about this is that it encourages people to view the causality backwards: that while there is no doubt that Laurence Kane was connected to Donna Lass (and so could genuinely have been a person of interest), her sad death had absolutely nothing in common with any of the Zodiac Killer’s confirmed murders – the connection implied by the poster would seem to be totally bogus, in every sense of the phrase.

The Donna Lass Postcard

All of which process of elimination leaves us with the Donna Lass postcard, which the History Channel episode also trawled over for some time:

Well… after all the above discussion, it perhaps won’t come as any great surprise that there is a high chance that this postcard (which, let’s face it, contains nothing new about her death, nor proof of her murder, etc) is also fake:

A postcard, supposedly from Zodiac, was received by the San Francisco Chronicle on March 22, 1971, with the implication that Lass was a murder victim. However, the postcard contained no proof, as Zodiac was known for including. In 1999 a retired detective revealed to me that a former Zodiac investigator had admitted to forging the Lass postcard.

I’m sorry, but I have to say that I find this whole thing unbelievably sad. A vivacious young woman gets abducted (and, in all probability, killed) and all people want to do is to use her death to manufacture elaborate links falsely entangling it with a serial killer. What kind of vacuous, cynical theatre is that? This isn’t a cipher mystery, this is a cipher tragedy: shame on those who do such things.

15 thoughts on “The Donna Lass cipher, solved… but no happy ending, sorry.

  1. Thomas on December 2, 2017 at 5:12 pm said:

    Up to now this series is a mere rehash of old stuff (now revealed by the ‘supercomputer’), the moon calender/dali days story included.

  2. Thomas: I hate to say it, but almost all the stuff the History Channel’s Zodiac presentation has taught me so far has been about how to do history badly, e.g. never acknowledge your sources, accept any old nonsense as fact, pretend that your Delphic supercomputer told you, don’t use any kind of critical thinking, etc.

  3. Rick A. Roberts on December 3, 2017 at 7:20 am said:

    The two lines of cipher on the Reward Poster decipher to ; FIRST LINE – ” CIOEUIEEWGSEIAEED “, or ” SEE I OWE YOU I(ONE) GEW(JEW) I SEE DEAD “. SECOND LINE, ” IIFNNNNLIEEIEYYN “, or ” II(TWO) FNNNN(FOREIGN) EYEEYE(EYES)LIE WITHIN “. The message is – ” SEE I OWE YOU ONE JEW IS DEAD “. ” TWO FOREIGN EYES LIE WITHIN “. Donna’s Parents were Russian/Jewish Immigrants and the Zodiac Killer was very prejudiced.
    Sandy Betts messaged to me that the drop of blood from CJB’s Pants should provide a DNA Clue to the Killer’s identity. I agree with her if it is an ample size sample, and it has not been contaminated in any way.

  4. Gene Rhea Tucker on December 3, 2017 at 10:19 pm said:

    I too am tiring of this series rather quickly, especially the pretense that the investigators are coming up with NEW things, which, in fact, are quite well-known OLD things. (“Look at this postcard! Wow! That’s crazy!” Dude, we’ve all seen the postcard.)

    I am hoping that their DNA evidence they collected way back in the first episode will prove that Zodiac didn’t commit the murder in Riverside. The show might be doing a decent job of proving that (a) Kane may have committed the Lass murder and perpetrated the Johns kidnapping and (b) that Sullivan may have committed the Bates murder. But proving who the Zodiac was? or coming up with something new with the cryptography? No, they haven’t done anything on that.

  5. A supercomputer named Carmel ?
    Carmel by the sea is the only town were it is illegal to wear high heels.
    What are the chances that any solution to the Zodiac will involve cribs ?
    Is this just software ? How about a real supercomputer like Deep Crack ?

  6. @nick: Is this the first time you’ve watched the History Channel? I’d say that for the last decade (if not longer) their new programming has been pretty bad.

    The older stuff was better, and they still show it sometimes, but how many times do you need to watch a D-Day documentary?

  7. Ken: a multi-part series on the Zodiac Killer could have been a big deal, because there is a lot to cover and plenty of opportunity for new stuff to be found. But perhaps the genre has become so televisually stale that this is just not possible any more. 🙁

  8. Cheer up this is only season one.
    It is in the History Channel’s intrest to milk this as long as possible.

    Who is the Zodiac Killer sending the messages to, no one. Therefor there is no key.
    He is using security through obscurity. He knows what he wants to say and what
    he doesn’t want you to know.

  9. The Donner Pass/Donna Lass was the only interesting item – but the small hole dug to determine if remains were there was not convincing – I wonder if the whole thing was a set up for filler.

  10. The reward is mine when this map finds her then the money will be used to find all zodiac victims .
    See the real ZODIAC KILLER KILL MAP https://www.youtube.com/watch?v=T1fcirUVke4&t=230s

  11. Jennifer on January 19, 2018 at 5:56 pm said:

    Hi. I’m trying to figure out how to subscribe or if there is need to do so. I did see where it mentioned “subscribers.” I’d really like to show you some things.

  12. Jennifer: there’s no need to subscribe to Cipher Mysteries, though it costs nothing and everything posted here is interesting. 😉 I’ll email you directly, hope that’s OK.

  13. Rick A. Roberts on January 20, 2018 at 7:49 am said:

    MY NAME IS … ” TEEDOSOHORETH “, ” THEODORE OSETH ” ? or ” THEODORE ETOSH ” ? Who had a License Plate Number, ” 3 888 ” CALIFORNIA ? Each of the three circles with an eight in the center in the ” MY NAME IS … “, reads ” O “, I think that the number ” 8 ” in each circle refers to the number ” 3 888 ” or three number eights on the license plate of the person in question.

  14. What! No-one else spotted the Donna Lass article appearing in the Netflix series, “Stranger Things”?

    Season 1, Chapter 6; “The Monster” (4:45 min. mark.)
    Scene opens with camera panning the top of a coffee table at Joyce Byers’ home. Subject article: “Missing Tahoe Nurse’s Family Offers Reward.”

    Nick, do I win anything? One free psychonaut’s float in a Samadhi isolation tank? A trip to the Upside Down world after a dose of MKUltra-grade LSD-25? A couple boxes of Eggo? — that is if you can get them in the U.K. :-p

    I swear; it pays to watch that show with one finger between ‘pause’ and ‘rewind.’ 😉

    Great acting, of course, from Brits and Americans. Being half-English and attending British school during my formative years, it never fails to amaze me how (young) English performers like Charlie Heaton can master the U.S. dialects – certainly enough to fool me. (Nick, please do make sure that it is indeed powdered sugar sprinkled atop my Eggo!)

  15. Rob PA: rest assured that I am not the kind of person who would narcotify another man’s Eggo. But thanks for the Stranger Things reference, much appreciated! (I’ve been meaning to watch the series for a while, and now I have a reason). 🙂

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