One of the most mysterious unsolved crimes in US history is one you might already be familiar with.
The Zodiac Killer, a callus murderer who brutally terrorised young California residents in the late 1960s, made newspaper headlines with their vicious attacks.
Known for targeting young couples in remote locations, the Zodiac Killer would shoot or stab his victims and send a series of letters with coded messages to authorities. He'd continue to taunt them the longer he went unknown.
For 54 years, leads have gone cold and the Zodiac Killer seemingly vanished into thin air.
But now, it's believed that a group of sleuths might just know who the killer was.
Professor Jen Bucholtz read a manuscript that she believed was connected to the string of murders associated with the Zodiac Killer.
Just a few days before, she'd been contacted by a stranger who claimed to know the identity of the mysterious serial killer.
A man called Dale Julin, a retired news presenter, approached Professor Bucholtz after his theory was dismissed by police and the FBI.
“Dale told me that in 2014, a homeless man, Chris Avery, turned up at the TV station he worked at wanting to speak to him," Bucholtz said.
“Chris claimed that his stepfather, Gary Francis Poste, was the Zodiac and that when he confronted him about it, Poste tried to kill him, so he went on the run."
And then, earlier this year, a group of amateur sleuths found a new piece in the puzzle that solidified their belief of who the Zodiac was.
Founder of The Case Breakers, Thomas Colbert, announced that a symbol used by the Zodiac was found on a wooden post near a property owned by the man they believed to be the mysterious serial killer.
The man in question was, indeed, Gary Francis Poste.
The Zodiac's letters would contain codes where letters had been substituted for symbols and readers had to correctly crack the code to decipher the message.
The first code was cracked within a week, the second one took 51 years, and two of them still remain unsolved.
During the five years when Dale tried to crack the code to find out if Poste's name was behind unlocking the Zodiac's identity, Poste passed away aged 80.
The only criminal record Poste had was when he'd been arrested for domestic violence in 2016 for allegedly pushing his wife down the stairs. He was found mentally incapable of standing trial so was referred to a state hospital instead.
“Dale emailed me in January 2020, saying he knew who the Zodiac was,” Professor Bucholtz explained.
“He asked if I would read his manuscript. About a third of the way through, I realised he’d got it.
“This must be it. Dale unusually reverse-engineered the case. Typically, you work from the beginning, forwards.
"But, in order to decode the letters, one must have the cipher key, which is Poste’s full name.
“There’s no other way to solve them. Using Poste’s name helped to find key information. Poste had the experience through his military years to create complicated ciphers.
“He lived in close proximity to the murders, wore size-10 military boots, prints of which were found at three crime scenes, and was an avid outdoorsman.
“There is nothing we know about Poste that eliminates him as a suspect.”
If Poste was indeed the Zodiac Killer, he would have escaped facing justice, outsmarting authorities for over five decades.