You can now leave comments on the articles that matter to you. Find out more here

Zodiac Killer decoded messages and people who claim they cracked his notes

Bruno Cooke May 13, 2022
zodiac killer decoded message
Photo by NY Daily News Archive via Getty Images


The Zodiac killer’s cryptic messages vexed cryptologists when he first started sending them in July 1969, and continued to do so into the 21st century.

However, in the last couple of years, codebreakers working either in collaboration or independently have claimed to have finally deciphered the Zodiac’s last messages.

It’s nearly 53 years since Donald Gene and Bettye June Harden cracked the Zodiac’s first cipher, on 8 August 1969. Now, there are people who say they’ve finally solved his last.

  • CULTURE: Who was Gary Francis Poste? Age and death of Zodiac Killer suspect
San Francisco murder victims; Betty Lou Jensen, David Faraday, and Darlene Ferrin, alleged to be victims of the Zodiac Killer.

Donald Gene and Bettye June ‘Valerie’ Harden were the first to solve one of the Zodiac killer’s codes

Don Harden studied at the University of Florida, Gainesville and completed a master’s degree in education. During his time there, he gained experience in cracking ciphers.

He and his wife Bettye June’s lives changed forever when the Vallejo Times Herald, the San Francisco Chronicle and The San Francisco Examiner each printed a letter from an unknown person – the Zodiac.

They printed them. The Hardens saw them. A week later, Don and Bettye cracked the 408-symbol cryptogram. They made front-page news on 9 August 1969.

According to History, Bettye is credited with discovering two “cribs”. They’re words or phrases a codebreaker expects to find in the message. 

Discovering them speeds up the process. Bettye guessed that the message would begin with the word “I”, and that it might even contain the phrase, “I LIKE KILLING”. Turns out, she was right. Its first three words were: “I LIKE KILLING”. Read the full passage here.

  • CELEBRITY: Who was Lawrence Kane, Zodiac suspect, and why the renewed interest in him?
Donald G. Harden, school teacher at Alisal High in Salinas, is the man who broke the code of the psychotic killer who calls himself “Zodiac” and brags he has already murdered five persons in the San Francisco Bay Area. The boastful killer has relayed messages to public and police through written letters and cryptograms sent to newspapers here and it was Hardes who unscrambled the mysterious notes.

But cipher Z-340 remained unsolved for over 51 years

On 8 November 1969, the Zodiac mailed a letter with another cryptogram. This one contained 340 characters and remained unsolved until very recently.

On 5 December 2020, an international team of ordinary citizens announced that they had de-coded one of the last holdout messages from the Zodiac killer.

The team included David Oranchak, a Virginian software developer; Jarl Van Eycke, a computer programmer from Belgium; and Sam Blake, an Australian mathematician.

The FBI verified the team’s work. However, the Bureau also stated that this latest decoding of a Zodiac message didn’t reveal the identity of the killer.

  • RELATED: Did the Zodiac Killer inspire The Riddler’s look in The Batman 2021?

French engineer Fayçal Ziraoui claimed to have cracked the Zodiac’s final message in June 2021

The New York Times reported on 22 June 2021 that a French engineer, Fayçal Ziraoui, had potentially ended a “50-year-old quest” by cracking the final Zodiac code.

“I was obsessed with it, 24 hours a day, that’s all I could think about,” the Times quotes him as saying.

The 38-year-old French-Moroccan business consultant is a former Ironman athlete and 3D animator. He likes a challenge. 

“I’ve never set limits on what I can learn,” he said. 

  • UP NEXT: The Black Dahlia Murder metal band takes its name from this gruesome unsolved killing

The Princess | Official Trailer

The Princess | Official Trailer

His efforts soon bore fruit. Two weeks after deciding he would decode the last of the Zodiac killer’s messages, he had de-coded it – at least, that’s what he says.

He used the encryption key that had only come to light the previous December (see above), combined with what the Times calls “creative code-cracking techniques”. He even claims to have discovered the killer’s true identity.

For more detail on how he went about unpicking the Zodiac’s last message, read IFL Science’s breakdown here. Ultimately, however, he reckons the message points towards Lawrence “Kane” Kaye – one of the main suspects in the case originally – as the killer.

Read more on Fayçal Ziraoui here.

How accurate is David Fincher’s retelling of the Zodiac killer’s story?

About 35%, according to’s FAQ section.

Thoughts? Comment Below
LOGIN to Comment
LOGIN to Comment
Have something to tell us about this article?
Let us know
Bruno is a novelist, amateur screenwriter and journalist with interests in digital media, storytelling, film and politics. He’s lived in France, China, Sri Lanka and the Philippines, but returned to the UK for a degree (and because of the pandemic) in 2020. His articles have appeared in Groundviews, Forge Press and The Friday Poem, and most are readable on Medium or