Zodiac serial killer's code cracked after 51 years

A San Francisco Police Department wanted bulletin and copies of letters sent to the San Francisco Chronicle - Eric Risberg/AP
A San Francisco Police Department wanted bulletin and copies of letters sent to the San Francisco Chronicle - Eric Risberg/AP

A team of codebreakers has deciphered an encrypted 340 character message sent 51-years ago by the so-called Zodiac killer, who was responsible for at least five murders in northern California.

The identity of the killer is still unknown and for decades experts have been baffled by the message he sent to the San Francisco Chronicle during his killing spree.

The message, one of several sent to newspapers during the killing spree, said: "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 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 will be an easy one in paradice death."

He was dubbed the Zodiac killer because of the bizarre array of symbols and capital letters he used in the messages he used to taunt the authorities.

Australian software engineer Sam Blake, American cryptographer David Oranchak and Belgian software expert Jarl Van finally unravelled the cypher, the FBI said.

Cracking the code relied on a combination of computer technology and human ingenuity to make sense of the jumble of symbols. The team sifted through 650,000 variations until some words appeared.

"We got really lucky and found one that had part of the answer, but it wasn't obvious,"  Mr Oranchak said.

File copy of a cryptogram sent to the San Francisco Chronicle in 1969 by the Zodiac Killer.
File copy of a cryptogram sent to the San Francisco Chronicle in 1969 by the Zodiac Killer.

The message's contents were chilling.

"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 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 will be an easy one in paradice death."

This is the first of three messages sent by the killer, who boasted that he had murdered 37 people.

The confirmed victims were a man and woman who were shot in their car in 1968, a woman who was shot in 1969, a man who was stabbed near a lake and a San Francisco cab driver.

Despite the breakthrough, Mr Oranchak was pessimistic about identifying the killer because the message contained no personal information.

Confirming the validity of the team's work the FBI said that it had reviewed numerous proposed solutions to the riddle over the years which were of no use.

"The cypher was recently solved by a team of three private citizens," it added.

"The Zodiac Killer case remains an ongoing investigation for the FBI San Francisco and our local law enforcement partners."