Codebreakers Solve Zodiac Killer's Z-340 Cipher

Misbar’s investigation found that the claim is true. On December 14, 2020, the FBI confirmed that a trio of private citizens used a computer program to crack the cipher that has been evading codebreakers for over half a century. David Oranchak, Sam Blake, and Van Eycke created a program that ran the cipher through around 650,000 possible solutions. On December 3, the terms “gas chamber,” “trying to catch me,” and “that wasn’t me on the TV show” were revealed by the program, meaning that the decoded messages fit the Zodiac Killer’s timeline.

One of America’s most infamous serial killers, and the subject of several films, TV shows, and books, the Zodiac Killer terrorized Northern California in the 1960s and 70s. He murdered at least five victims, mostly young couples. In one of his many letters to the police, he claimed to have killed at least 37 victims. Although there is much public speculation about who the Zodiac Killer was, his true identity remains unknown to this day. On November 8, 1969, the S.F. Chronicle received a 340-character cryptogram from the Zodiac Killer. The cryptogram is below.

Despite endless efforts by cryptologists, law enforcement, and private citizens to break the code, it went unsolved until Oranchak, Blake, and Eycke created their computer program. After fully decoding the message, the trio submitted it to the F.B.I. on December 5. 

The message reads: “I hope you are having lots of fun in trying to catch me that wasn’t 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.”

In his previous messages, the Zodiac Killer had discussed creating “slaves” to work for him in the afterlife by murdering them. 

About cracking the code, Blake said: “Not only were we lucky enough to find the needle in the haystack, but we were lucky enough to pick the right haystack in order to start searching for the needle.” In the video below, Blake explains just how the trio’s computer program managed to crack the code.

There are two more uncracked ciphers believed to belong to the Zodiac Killer, but the Z-340 cipher was the most notorious.