A cipher from San Francisco’s notorious “Zodiac Killer” of the 1960s and '70s apparently has been solved after 51 years.

A code-breaking team with members in the U.S., Australia and Belgium claims it cracked the decadeslong mystery and reported its breakthrough to the FBI, the San Francisco Chronicle reported Friday.

“The FBI is aware that a cipher attributed to the Zodiac Killer was recently solved by private citizens,” FBI San Francisco spokesman Cameron Rogers Polan said in a statement to Fox News. “The Zodiac Killer case remains an ongoing investigation for the FBI San Francisco division and our local law enforcement partners.”

San Francisco police circulated this composite of the Bay Area's "Zodiac" killer. At left is a drawing from witnesses to slaying of a cab driver in San Francisco. The amended drawing on the right was based on further questioning of the witnesses. 

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Rogers Polan added, “The Zodiac Killer terrorized multiple communities across Northern California and even though decades have gone by, we continue to seek justice for the victims of these brutal crimes. Due to the ongoing nature of the investigation, and out of respect for the victims and their families, we will not be providing further comment at this time.”

Expert code breaker and team member David Oranchak said the cipher’s text includes: “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 paradise all the sooner because I now have enough slaves to work for me,” the Chronicle reported.

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Oranchak has spent years working to solve the Zodiac Killer’s “340 Cipher.”

“Last weekend, a team I’m on solved the 340 and submitted it to the FBI,” he told the Chronicle in an email sent Friday. “They have confirmed the solution. No joke! This is the real deal.”

The Zodiac Killer was responsible for five murders in the San Francisco area in 1968 and 1969.

After decades of investigation, new articles and books, his identity remains a mystery and he has taken his place in the pantheon of history’s most infamous serial killers.

Unlike other serial killers, the Zodiac Killer taunted police with enigmatic ciphers and bizarre letters to the newspaper. In them, he claimed as many as 37 victims.

The Chronicle received the 340 Cipher in November 1969.

Months earlier the paper received a cipher from the Zodiac Killer that had 408 characters.

The 408 Cipher was solved by a Salinas teacher and his wife, according to the Chronicle.

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It said little beyond, “I like killing because it is so much fun,” the paper reported.