French software engineer may have cracked the Zodiac killer's code

In the late 1960s and early 1970s, a serial killer known as Zodiac killed at least five people in Northern California. The case has never been solved. The Zodiac Killer famously sent four ciphers to local news outlets, and two have never been solved even though amateur and professional cryptographers have spent decades attempting to crack them. Now, French software engineer Fayçal Ziraoui claims that that after just two weeks of trying, he's successfully decoded the letters, including one that reveals the name of the killer as "KAYR" which he believes is a miscoded spelling of the last name of Lawrence Kaye who has long been a suspect. The online community of Zodiac sleuths not only doesn't believe that Ziraoui succeeded but is furious at his hubris. From the New York Times:

In hindsight, Mr. Ziraoui realized he had been a little tactless, brazenly bursting into a tight-knit community with what he presented as definitive solutions.

"He came in and told them 'end of the game'," said Youssef Ziraoui, his brother and a journalist in Morocco. "But these people don't want the game to end."

And it remains unclear whether the case — which has for decades consumed police detectives, generated dozens of stranger-than-fiction claims and inspired a blockbuster movie — will ever be solved. The F.B.I. and the San Francisco Police Department, to which Mr. Ziraoui sent his findings, declined to comment, citing the ongoing investigation[…]

Around 2 a.m. on Jan. 3, an exhausted but elated Mr. Ziraoui posted a message entitled "Z13 — My Name is KAYE" on a 50,000-member Reddit forum dedicated to the Zodiac Killer.

The message was deleted within 30 minutes.

"Sorry, I've removed this one as part of a sort of general policy against Z13 solution posts," the forum's moderator wrote, arguing that the cipher was too short to be solvable. The moderator declined to be interviewed by The New York Times.

Similar dismissive comments were made on other forums. Many of the comments went down arcane, and sometimes nonsensical, rabbit holes; others said Mr. Ziraoui's methods were too convoluted.

image: crop of Zodiac's letter sent to the San Francisco Chronicle on November 8, 1969 (public domain)