From 1968 to 1974, Northern California was terrorized by a mysterious killer who taunted the police and forced the press to publish his coded messages.

It’s a disturbing case that was documented in David Fincher‘s 2007 film Zodiac. But without a real resolution to the mystery, there’s no telling how much the movie left out.

Only five murders have been conclusively attributed to the so-called Zodiac Killer, but many others are suspected. In his last letter to the press in 1974, the killer claimed a body count of 37. And though many attempts have been made to connect various people to these crimes — Arthur Leigh Allen, Ross Sullivan, and Lawrence Kane are among the favorites — all we can say for certain is that Ted Cruz is the junior Senator from Texas.

All these decades later, despite two of his victims escaping with their lives, and three eyewitnesses watching him walk away from the scene of a killing, the Zodiac has never been positively identified. At this point, it is likely he never will be.

But that doesn’t mean there isn’t still progress to be made on one of the most fascinating manhunts in the history of American crime. In addition to police investigations into possible DNA evidence extracted from the back of licked stamps, there are countless amateur sleuths and true crime fanatics who still pore over all the available evidence, searching for clues. There’s an entire thriving subreddit devoted to the mystery.

Generally these hobbyists are unqualified to add anything but confused speculation to the mystery. But every once in a while some people with real expertise come along and uncover something of real significance.

That’s case of Jarl Van Eyck, Sam Blake, and David Oranchak. They are amateur code breakers with some real skills in mathematics and programming to bolster their hard work.

For the last 7 months, these three men collaborated from across the world — Van Eyck in Belgium, Blake in Australia, and Oranchak in the US — applying their skills to solve one of the greatest remaining mysteries of this case: the coded message known as Z 340.

Let’s Crack Zodiac – Episode 1 – Graysmithwww.youtube.com

Along with letters written in plain English (with some idiosyncratic spelling errors) the Zodiac sent four ciphers to the press — messages encoded in his personal set of symbols. He promised that his identity would be revealed when police cracked the first message, known as Z 408. That was a lie.

The 408 symbols of that first cipher ended up being cracked not by police or the FBI, but by Donald and Bettye Harden — a schoolteacher and his wife who took up the challenge when the message was printed in the newspaper. Among the disturbing contents of the message were the words “I will not give you my name.”

A later cipher that once again promised to reveal his identity is thought to have been another ruse. A probable solution to the message contained in the Z 13 cipher sent in 1970 is “Alfred E. Neuman” — the name of MAD Magazine‘s cartoon mascot.

Still, as cagey as he was, the fact that amateurs had managed to crack his code within a week seemed to have rattled the Zodiac. His second cipher — sent several months after the first — contained 340 characters, and was far more complex. It was so complex that it took more than 51 years to solve.

On Monday, December 11, 2020, David Oranchak uploaded a video to his YouTube Channel announcing that himself, Van Eyck, and Blake had finally solved the puzzle.

Others have claimed success before, but their solutions have been messy, and the messages revealed did not seem to match the sick sense of humor represented in the rest of the Zodiac’s writing. Not so with Oranchak and his collaborators. Using a combination of custom software, hard work, and lateral thinking, they managed to uncover the following message from the mysterious killer:

I HOPE YOU ARE HAVING LOTS OF FUN IN TRYING TO CATCH ME

THAT WASNT 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

Let’s Crack Zodiac – Episode 5 – The 340 Is Solved!www.youtube.com

The idiosyncratic spelling of paradise as “paradice” matches other letters. In addition, the message references the Zodiac’s stated belief that his victims would serve him in the afterlife.

As to the mention of a TV show and gas chambers, that refers to an event that took place just weeks before the cipher was sent, when a mental patient called into a live broadcast claiming to be the Zodiac Killer and espousing a fear of being sent to the gas chamber.

It seems certain this is the message that remained trapped in those symbols for more than 50 years. Unfortunately, in terms of the killer’s identity, it seems to be as useless as his other messages.

Maybe it contains some hidden clues that will one day be pieced together — maybe this revelation has moved us one step closer to uncovering the truth. Until then, the identity of the Zodiac Killer remains a mystery.