One of America’s most notorious killers had two chilling words that helped solve 51-year mystery

One of America’s most notorious killers had two chilling words that helped solve a 51-year mystery.

Back in the 1960s, a murderer began terrorising Northern California and killed five known victims between December 1968 and October 1969.

However, it's possible the number was much higher during the peak of his murderous rampage.

The unidentified criminal was dubbed the pseudonym of Zodiac Killer, because of his messages signed with a zodiac symbol, and he frequently goaded authorities with a series of coded letters.

The letters allegedly outlined in specific detail how each murder occurred - details only the real killer could know.

The issue is that all the notes, some of which were even found at the crime scenes, were totally indecipherable and written as a series of random symbols and invented characters which needed a key to decode.

In one chilling message, littered with the spelling mistakes, repetition and a lack of punctuation, the killer allegedly wrote: "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 whey 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."

The 340-character cipher has since been a mystery to investigators for all these years.

That was until Australian software engineer Sam Blake, American cryptographer David Oranchak and Belgian software engineer Jarl Van claimed they finally made sense of the letter a whole 51 years later.

They made over 650,000 attempt combinations until they finally narrowed down on two pivotal words: "gas chamber."

Now, while the trio were able to crack the code - they weren't able to identify the person person it.

The Zodiac Killer's identity still remains a mystery but is thought to be encoded within a cipher in one of his several cryptic notes.

In 2020, the FBI confirmed that the message had been deciphered.

In an official statement, they wrote: "The FBI is aware that a cipher attributed to the Zodiac killer was recently solder by private citizens.

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

"The Zodiac killer terrorised multiple communities across Northern California and even though decades have gone by, we continue to seek justice for the victims of these brutal crimes."

It concluded: "Due to the ongoing nature of the investigation, and out of respect for the victims and their families, we will not be providing any further comment at this time."