Code-breakers have cracked a 340-character cipher 51 years after it was purportedly sent to the San Francisco Chronicle by the so-called Zodiac Killer, the FBI has confirmed.
The killer, who was never caught, murdered five people in stabbings and shootings that terrorised the San Francisco Bay area in the late 1960s.
The message was one of several sent to newspapers during the killing spree.
The code was solved by three people from the US, Belgium and Australia.
“I hope you are having lots of fun in trying to catch me. I am not afraid of the gas chamber because it will send me to paradice (sic) all the sooner because I now have enough slaves to work for me,” the message reads, without throwing any light on the killer’s identity.
Video posted on YouTube by Virginia web-designer David Oranchak says he cracked the cipher along with Australian applied mathematician Sam Blake and Belgian Jarl Van Eycke, a warehouse manager and code-breaking software engineer.
Mr Oranchak described the message as “more of the same attention-seeking junk from Zodiac”. The code-breaking team, who used human ingenuity and software to decipher the message, dedicated their efforts to victims and relatives of those murdered.
Confirming the code-breaking achievement, the FBI said it continued to seek justice for those killed.
This is not the first encoded message attributed to the killer, according the San Francisco Chronicle. Two others remain to be decoded – one of which may contain the killer’s name.
The series of murders began in December 1968 with a man and a woman shot dead in their car. In July 1969, another man and woman were shot, but he survived.
Later that year, a couple were stabbed next to a lake – he survived. In October 1969, a cab driver was shot dead in San Francisco.
The killer, who has never been charged or identified, claimed to have murdered 37 people in letters to newspapers, but investigators have worked on the basis of seven victims in total, five of them homicides.
The murders inspired two films – Zodiac, starring Robert Downey Jr, and Dirty Harry in 1971 featuring Clint Eastwood as a tough San Francisco detective.