Thomas Dougherty’s “code theory”

Thirty-seven years ago, a man named Thomas Dougherty came up with a Zodiac “code theory”, and mailed dozens of bizarre letters from the Hotel Warfield in San Francisco to United States federal judge Oliver Carter.


The letters were recently unearthed again from the San Francisco Public Library by researchers Mark (traveller1st) and Di (Zamantha). Di paid a visit to the library, obtained copies of all the files, and also discovered that they had been previously found by “Goldcatcher / Blaine Blaine”, the person who originally promoted suspicions that Richard Gaikowski was the Zodiac killer (read more here and here). Goldcatcher refers to Dougherty in his report:

Some of the most pathetic Zodiac suspects included " my Uncle Bubba the Zodiac" – this Zodiac suspect turned out, like most of the others, a joke foisted on an ignorant mass media; and someone living in a tenderloin hotel room with a bottle of wine who got drunk and began believing the son of Howard Hughes was the Zodiac according to his written decoding illusions.

Di generously gave me a copy of the Dougherty files, which I’ve scanned and put online. You can read the letters in their entirety here.

Was Thomas Dougherty on to something with the Zodiac ciphers? Let’s examine his approach. Here’s how he describes his method:

Several tricks were employed, the first being that each letter represented a word. Using the letters only I figured out the words going down and then going up, forming new words wherever possible. That was trick two and three. Hidden words was four. Then rearranging the letters was trick five, six, seven and eight. Not to forget at this time that in the symbols the crossed circle was used as a L, but was a S in just one instant. Trick number nine was read it from the way it appeared in the news-paper. Ten was the grand-daddy of all using the last letter of Marysville and designate it by a plus. There are six master copies note the trick which had to be performed in the last page of the cipher, which is I believe page 19.

OK, well, that’s confusing. I couldn’t glean much from his own description, so I reverse-engineered his technique by examining his work. He based his work on the 340 cipher, and created a grid of symbols and letters, containing 17 columns, and standing 40 rows tall:


(click for full version)

He formed the grid by re-arranging the symbols of the 340 cipher. First, he identified all the “normal” letters A through Z as they appeared in the cipher text:

For some reason, he changed some of the V’s into R’s:

He referred to this as “Trick 7”, which he applied after re-arranging the cipher text:

Dougherty constructed his grid by taking the A through Z symbols and writing them in order:

Then he wrote out everything else:

He pasted these two sections together to form his grid layout, and then used his substitution key to make plaintext letter assignments. This appears to be his substitution key:

The two alphabet rows at the top are presumably the plaintext letters. I’m not sure why he made two rows. But the assigned symbols don’t exactly match the substitutions in the grid. These are the actual substitutions:

For some reason, he organized some of the “normal” A through Z ciphertext symbols at the top of the key, right under the plain text alphabet. He then moved the remaining “normal” A through Z letters to fill out the row underneath the plaintext alphabet. For example, if you look at the above assignments for the plaintext letter A, you’ll see these assigned symbols: , , , , and . To form his key, he removed the normal symbol from the column for plaintext letter A, and put an under the column for plaintext letter D. Similarly, he removed and placed an under the column for T. Following this procedure for the remaining “normal” letters, he arrived at this key:

I’m not sure why he moved under the column for X, or why he even re-arranged the normal letters in the key in the first place. Does it even matter? Here is the result of applying his substitution key to the re-written cipher text:

To write out his solution, Dougherty distilled this down to the first nine pairs of lines, and removed anything that isn’t a normal letter of the alphabet:

Then he wrote out the letters in order from top to bottom, starting at the leftmost column:

And wrote out the letters from the same column from bottom to top:

This results in the following stream of letters:

I’ve included some of his transcription mistakes in the above figure.

Now, here is where his system really went off the rails. Up to this point, the manipulations of the cipher text were fairly reasonable and systematic. But he inexplicably substituted each letter with entire words to construct a bizarre story with characters Dougherty believes are involved in the crimes:

OK – I stopped after nine lines, because it goes on like this for a very long time, and I’ve already tortured you enough. You can see the full example here.

Here is the list of words he used in the full example, organized by the letters they replaced:

  • A: A, Aid, Alex, All, And, Angry, Ann, Anns, As, Asked, Asleep, At, Attorney
  • B: Bad, Battled, Beat, Behind, Bellis, Big, Bloody, Bob, Boob, Both, Bought, Brilliant, Buried, But
  • C: Car, Castle, Crazy, Cut
  • D: Dark, Dead, Decapitated, Donna, Dunbar
  • E: Educator, Edward, Edwards, Evil
  • F: Fifth, Fight, Fighting, First, Forest, Fought
  • G: Got, Gottlieb, Graves, Gruesome, Gun, Gunman, Gunned
  • H: Hate, Here, Hid, Him, History, Hospital, Hughes, Hurt
  • I: Identified, In, Incline, Innocent, Intelligent, Iodine, Irene, Is
  • J: Junior, Juniors
  • K: Killed, Killer, Killers, Knifed, Knifing
  • L: Land, Lass, Letterman, Lieutanant, Lieutenant, Linda, Logcutter, Lone, Lost, Louis, Loved
  • M: Massacre, More, Murdered, Murderer, Murderers, Murders, Must
  • N: Nancy, Napa, Near, Newsreporter, Nigra, Now, Nudist, Nurse, Nursed
  • O: Off, Office, Officer, Officially, Often, Over, Own
  • P: Poison, Poisoned, Poisoner, Policeman, Radetich, Ravine, Ray, Rays, Right, Robert, Roberts, Ruthless
  • S: Saw, Schwartz, Scwartz, Sheriff, Sheriffs, Shot, Spoke, Stabbed, Stabbing, Station
  • T: Tahoe, Throat, Too, Took, Tramps, Trash, Trouble, Two
  • U: Unusual, Use, Used, Usually
  • V: Vicious, Viciously, Victim
  • W: Wanted, Willed, Winos, Woods, Wounded
  • Y: You, Your
  • Z: Zodiac

Dougherty gave no justifications for his list of words. He simply drew them from some pre-determined set of names, locales, and circumstances that fit his story. It’s really easy to come up with any story you want using this technique. Let’s try it!

Consider the line:

We can produce the following by playing his acronym game:

There is no limit to the list of words you could choose from to write out a story. Worse, he re-wrote the letters in different orders (such as diagonally), and continued his word substitution game across many pages of his numerous letters. I won’t torture you further by including those here, but you can see them all in the files here.

This is about as far as I got in trying to understand Dougherty’s madness. His letters ramble on, a desperate jumble of deluded thoughts. Who was Thomas Dougherty? Was he mentally ill? Was he really a drunk? Why did he sign his name in some places with the suffix “MDC”? What does that stand for? Some reflections of his personality appear in his letters to justice Oliver Carter:


He felt like he was putting himself at risk by writing about his code theory. Here are some of his appeals to justice Oliver Carter:

Please verify receiving to make certain postal authorities are not seizing my mail

Maybe you don’t believe. If you do, fix me up with a court order. Otherwise, I am going to get in trouble and maybe get myself killed. I’ve done my best. Now there are five loose and I do not know what Bill looks like other than big, heavy, maybe Norwegian, last name may be Anderson.


He was not fond of the FBI, who apparently would not assist him by taking action on his theory:

(His little cryptogram there clearly decodes to read: “cunt in a whore house“.)


Who are the people he mentions in his forced and lengthy solution?

He focuses on his suspect, Ray Hughes, whom he claims is the magician son of Howard Hughes and a famous actress:

You will have to give much credit to this man for the genius exhibited in the composition of this cipher. It may have been a natural for him. A self-made man who was not to lean on the wealth that others in his family posessed. Professional musician, being taught music one must believe at the University of Milwaukee receiving a MA degree. He supported himself at times by just being on the bum in search of further knowledge, did just about everything in order to be independent and make a buck. Bouncer, Trombonist, Organist, taught Piano, parked cars and among others a magician.
He is not to blame for this slaughter, WW2 made a butcher out of him and after being cited as a hero of the Marine Corps. Carlsons Raiders he just was not conditioned for civilian living I believe he joined the Korean War just to satisfy his lust for killing. Maybe there was no lust for killing. Furthermore he had a bad case of typhoid-fever which just about took his life. Just when he acquired this wealth of his own is not known, and when he found out that Howard R. Hughes was his real father and a prominent movie star was his mother when he suddenly became very angry and commenced his wave of killing.

Another character in his story is Louis Gottlieb, who was apparently involved in the killings.

He believes the players in his drama performed their crimes partly to make the code work properly:

He brings up many other names, and I have gotten lost trying to make sense of his delusional narrative. In one letter he talks about how he yelled at a man for withholding his mail, and how he learned about devil sacrifice by studying strange people in hotels.

Was Dougherty simply trying to generate some cash for his friends, who he claims were falsely jailed for their crimes?

$10,000 for a pacemaker and eye transplant???

He writes about his own investigations, and his continuing frustration at the lack of cooperation by authorities:

Then he appears to give up:

I don’t know why Dougherty targeted Oliver Carter with these rambling letters. Was Dougherty really a car thief, which he mentions in the above letter? Carter died in 1976, less than one year after Dougherty’s letters were sent, so we can’t ask him about it. There is an interesting (and likely meaningless) connection to the Zodiac killer: Carter presided over the trial of Patty Hearst, the famous newspaper heiress who was kidnapped and recruited by the Symbionese Liberation Army. The Zodiac killer referenced the SLA in one of his letters.

Dougherty’s letters give us a bizarre and interesting glimpse of the effects the Zodiac case has on people. The mystery of the Zodiac case is a powerful nectar that attracts the madness of many people. This aspect of the case has a life of its own, which is simultaneously fascinating and depressing to me. How much of our own lives have we confidently constructed as truths, but instead resemble Thomas Dougherty’s imagined phantoms?

(Hat tip to Mark and Di for their generosity and continuing research efforts)