Cracking Killer Codes
How cryptologists solve crimes
The Zodiac Killer
The serial killers who keep people awake at night aren’t Ted Bundy or Jeffrey Dahmer. It’s the monsters who’ve never been identified or caught.
One of these beasts is arguably the most famous unsolved American serial murderer. The Zodiac Killer (Zodiac) is a legendary figure in crime history.
This assassin murdered five known victims in the San Franciso Bay Area. The crimes were committed between December 1968 and October 1969.
Zodiac targeted three young couples in rural, urban-suburban settings. His only lone victim was a cab driver. Experts believe Zodiac may have killed more than 30 other people.
Ciphers
The Zodiac case has many fascinating aspects. His use of coded messages made him interesting to cryptographers who break ciphers.
From 1966 to 1974, the unidentified serial killer wrote coded messages. He used cryptic icons or ciphers to brag about his murders.
During that period, he sent more than 20 written communications. The messages found their way to local police and newspapers.
The killer’s use of codes and self-reference earned him the Zodiac moniker. Many of his cipher symbols linked back to a 13th-century alphabet, “the Zodiac alphabet.”
Also called encryption algorithms, ciphers are systems for encrypting and decrypting data. A cipher converts the original message by using a key. It converts plaintext into ciphertext.
The newspapers printed the ciphers (or cryptograms). Why? The Zodiac threatened to kill more people if his instructions weren’t followed. He sent his first coded letter to three different papers in the Bay area.
Each letter contained a different cipher part.
The results of the first coded message
Zodiac’s first code was much simpler than his later efforts. It was solved by hand a week later, on August 8, 1969.
Several people worked on breaking the initial code with amateur cryptologists. Donald Gene and Bettye June Harden ultimately broke the cipher.
The message, complete with misspelled words, read:
“I LIKE KILLING PEOPLE BECAUSE IT IS SO MUCH FUN IT IS MORE FUN THAN KILLING WILD GAME IN THE FORREST BECAUSE MAN IS THE MOST DANGEROUS ANIMAL OF ALL TO KILL SOMETHING GIVES ME THE MOST THRILLING EXPERENCE IT IS EVEN BETTER THAN GETTING YOUR ROCKS OFF WITH A GIRL THE BEST PART OF IT IS THAT WHEN I DIE I WILL BE REBORN IN PARADICE AND ALL THE I HAVE KILLED WILL BECOME MY SLAVES I WILL NOT GIVE YOU MY NAME BECAUSE YOU WILL TRY TO SLOW DOWN OR STOP MY COLLECTING OF SLAVES FOR MY AFTERLIFE EBEORIETEMETHHPITI."
Unsolved for more than fifty years
One of Zodiac’s other three coded messages was Z-340. It contained 340 characters, and unlike the first message, it remained unsolved for 51 years.
Why? It contained a spelling error, which made the cipher unbreakable.
The world’s best experts, including cryptologists, mathematicians, and detectives, couldn't crack the code. Even the NSA, CIA, and the FBI couldn’t.
On December 5, 2020, an International team finally deciphered the Z-340 code. American software engineer David Oranchak, Australian mathematician Sam Blake, and Belgian programmer Jarl Van Eycke worked together.
A simple error
It was extraordinary that Zodiac created a cipher that fooled the FBI for decades.
The killer didn’t make the effort to give his spelling a quick double-check. Since he was writing coded notes related to murder, he couldn’t ask for proofreading help.
Even after the code for Z-340 was deciphered, it contained no new clues. All it indicated was that the killer had some odd delusions. Also, he needed to work on his spelling.
The code breakers deduced that Zodiac may have been inspired by The Most Dangerous Game. The movie was about a man hunted by an aristocrat for kicks.
How was the Zodiac Code cracked?
Amateur cryptologist David Oranchak unsuccessfully worked on the Zodiac’s cipher for 15 years. Then, he received a comment on one of his YouTube videos.
Oranchak responded to the commenter, which sparked a collaboration. The Virginia-based web designer and the commenter, Australian-based mathematician Sam Blake, joined forces.
Not long afterward, Jarl Van Eycke, a day warehouse operator in Belgium, joined the pair. The three-member team worked together to crack the code.
Oranchak, Blake, and Van Eycke used software to help them break the cipher. They started by finding as many possible reading directions that could be used if the cipher was transpositional.
The Zodiac’s 350-cipher encryption scheme is available in a 1950s Army cryptography field manual. Blake explained how the killer transposed his code, so it had to be read diagonally. This made it more complicated to decode.
The three worked remotely to find the solution. But Van Eycke wrote the software that eventually solved the puzzle.
Supercomputers helped break the code
The team ran 650,000 possible solutions through the University of Melbourne supercomputer. It helped them decrypt the message.
Blake said, “There’s been a lot of solutions in the past that have required artistic creativity.”
He said they had to perform “A lot of bending and massaging of the cipher to get it to make a few legible words.”
Once they had words, Blake said they could make “something like a sentence.”
Then, they could decipher “The name of somebody who could be associated with the case.”
Blake said, “We looked at different possible ways you could read the cipher — what other reading directions could they have taken in terms of trying to write it out — and we then ran them through supercomputers and looked for a solution in that direction.”
They got lucky, and Oranchak found a key solution. The cipher could be transposed to reveal message fragments.
Smaller text blocks
Those included “hope you are,” “trying to catch me,” and “or the gas chamber.”The message was broken into smaller blocks.
This gave them clues that the message wasn’t transcribed in one big block as it was presented but instead was broken into three smaller blocks of text: nine lines, followed by nine lines, followed by a final two.
By starting in the top left-hand corner, then moving down one line and across two spaces to get the following letter, a key emerged that could be translated into letters and words.
For Oranchak, this made the solution seem real, as it fit with the events around the time it was received. The rest of the message also seemed in character for the Zodiac Killer.
The team submitted their solution to the FBI, who has since confirmed it. They released a statement that said, “The FBI is aware that a cipher attributed to the Zodiac Killer was recently solved by private citizens.”
The FBI added that the identity of the Zodiac Killer is still being investigated and not solved as some had claimed in October.
Z-340 text
The letter “B,” for instance, was represented by “?7”, “c” by a simple “9”, and “A” by a whole load of symbols unavailable on a keyboard.
Anyone can see these symbols shown in a video released by the team on YouTube.
Through the use of this method and some slight adjustments by ignoring a few words that stood out before transposing the text, a message was revealed:
I HOPE YOU ARE HAVING LOTS OF FUN IN TRYING TO CATCH ME
THAT WASNT ME ON THE TV SHOW
WHICH BRINGS UP A POINT ABOUT ME
I AM NOT AFRAID OF THE GAS CHAMBER
BECAUSE IT WILL SEND ME TO PARADICE ALL THE SOONER
BECAUSE I NOW HAVE ENOUGH SLAVES TO WORK FOR ME
WHERE EVERYONE ELSE HAS NOTHING WHEN THEY REACH PARADICE
SO THEY ARE AFRAID OF DEATH
I AM NOT AFRAID BECAUSE I KNOW THAT MY NEW LIFE IS
LIFE WILL BE AN EASY ONE IN PARADICE DEATH
A correlation of words
Oranchak explained, “Of all the things that stood out (to me) was the line ‘that wasn’t me on the TV show.’”
“At this point I jumped out of my chair because I knew the cipher was received on November 8, 1969, which is about two weeks after someone calling themselves Zodiac called into a TV talk show hosted by Jim Dunbar.”
Oranchak said, “While the caller was on the air, he said, ‘I need help, I’m sick, I don’t want to go to the gas chamber.’”
The Zodiac was not the only killer who used coded messages
Most of the Zodiac’s encrypted messages have been cracked. As of 2024, some remain unsolved. The killer was never caught.
There have been other famous murder cases involving encryptions. Convicted wife murderer Henry Debosnys left ciphers in the late 1800s.
The mysterious Somerton Man in Australia left an encrypted note in 1948. Later, in the 1970s, the German terrorist group RAF used advanced encryption systems.
Many other stories of this kind of coded messages exist. They may or may not have been solved. They involve both resolved and unresolved unsolved crimes.
And the identity of the Zodiac killer? They may never be found. Many presume the famous serial killer died years ago.
But then, anything is possible when it comes to serial killers and uncovering their identities.
Spooky.
Brilliant writing