Meet Fayçal Ziraoui, the man who claims to have cracked the Zodiac Killer's cipher

Mafalda Costa June 23, 2021
Meet Fayçal Ziraoui, the man who claims to have cracked the Zodiac Killer's cipher


The Freeway Phantom, Jack the Ripper, the Zodiac Killer – all serial killers whose identity is yet unknown. But in the age of the online self-proclaimed detective, there is one man whose findings have left the internet in shambles. Who is Fayçal Ziraoui, the man who claims to have cracked the Zodiac Killer’s last cipher?

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Who is Fayçal Ziraoui?

Fayçal Ziraoui caused an uproar on the internet today, 23 June, after he claimed to have cracked the Zodiac Killer’s unsolved last cipher, potentially ending a 50-year-old investigation.

Ziraoui is a 38-year-old French-Moroccan business consultant.

Born and raised in Morocco, Ziraoui studied in France, where he graduated from École Polytechnique and HEC Paris, the country’s top engineering and business schools. 

According to The New York Times, Ziraoui always loved a good challenge – and going into the pandemic, code-solving turned into a hobby.

So when he stumbled across an article in a French magazine in December saying no one had ever solved two ciphers attributed to the Zodiac killer, he thought: “Why not me?”

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Two weeks after embarking on the quest, Ziraoui believed he had cracked the two remaining ciphers – one 32 characters long and a 13-character cipher preceded by the words: “My name is __.”

Filled with excitement, he went online to share his findings, posting messages and videos online on some of the many Zodiac Killer forums – including a 50,000-member Reddit forum dedicated to the serial killer.

However, his post was deleted soon after, with the forum’s moderator writing: “Sorry, I’ve removed this one as part of a sort of general policy against Z13 solution posts,” claiming the cypher was too short to be solved.

Who is the Zodiac Killer?

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The Zodiac Killer is an unidentified American serial killer who terrorized the San Francisco Bay Area in the 1960s and 1970s.

He is believed to have murdered at least five people in northern California between 1968 and 1969, but was known to boast of 37 killings in his letters.

The murders were the subject of intense investigation and media coverage, particularly because of the killer’s taunting letters to newspapers and phone calls to police.

The letters, sent between 1969 and 1974, were signed with a symbol resembling the crosshairs of a gunsight and typically began with the phrase: “This is the Zodiac speaking.”

Did Fayçal Ziraoui really crack the Zodiac Killer’s cipher?

Ziraoui said he applied the same 340-character cipher he read about in December to the 32- and 13-character ciphers – the former related to the location of a bomb set to go off at a school in autumn 1970 (but which never did) – and the latter to the killer’s name.

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A letter and a blood-soaked piece of shirt have alerted San Francisco police to the possibility that the slayer of cab driver Paul Stine might be the same man how killed four others in the Bay Area in the last year. This note was mailed to the local paper along with a piece of cloth believed torn from the cab driver’s shirt. The note stated that the writer was the killer “of the people in the north bay area”–a reference to the unsolved slayings at Lake Berryessa in Napa County and Vallejo.

The online code-crackers were sceptical of the engineer’s findings, with one particular user saying: “For my part I don’t believe it for a second. When he says it took two weeks to crack the Z32 and an hour for the Z13, I think that sums it up pretty well.”

David Oranchak, leader of the team that cracked the 340-character cipher, told The New York Times he was sceptical of Ziraoui’s solution.

However, cryptographers David Naccache and Emmanuel Thomé said Mr Ziraoui’s code-cracking methods were sound and should be considered by police investigators.

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Mafalda Costa is a second year BA Journalism student originally from Portugal. Her main passions if life are music, arts and culture, while she's particularly knowledgable on cinema and anime.