For half a century, the Zodiac Killer case has been a mystery both police and armchair murder investigators have been desperate to solve.
The serial killer claimed the lives of five people in and around the US city of San Francisco between 1968 and 1969.
The anonymous murderer then taunted the authorities and the Californian public with coded letters they sent to local newspapers.
Ever since, the Zodiac killer has become something of a cultural icon, inspiring fictional characters, films and TV shows – including new Disney+ documentary series The Most Dangerous Animal of All.
In October 2021, a cold case investigation team known as the Case Breakers claimed to have finally unmasked the killer as Gary Francis Poste.
So who is Gary Francis Poste, is he really the Zodiac Killer – and who were his alleged victims?
Who is Gary Francis Poste?
Gary Francis Poste was a former US air force serviceman who was brought up in California.
He died at the age of 80 years old in August 2018.
Various media reports suggest Poste was a violent man.
According to the San Francisco Chronicle, the newspaper was contacted six years ago by a male relative of Poste who said he lived in the town of Groveland – around 150 miles from San Francisco.
Gary Francis Poste lived in rural California (image: Adobe)
This relative accused Poste of being the Zodiac Killer and of having tried to kill him with a hammer.
When the newspaper contacted Californian police, they said there didn’t appear to be any connection between Poste and the Zodiac Killer.
Poste’s former daughter-in-law, Michelle Wynn, also accused him of being the serial killer, the paper said.
Ms Wynn said she had moved away from California to be safe from Poste.
In January 2022, the US version of The Sun obtained a police report which documented how Poste pushed his wife Mary, then aged 74, into a wall and broke her pelvis in four places in 2016.
The news organisation also revealed the incident caused US authorities to lock him up in a mental health facility because it was found he was too mentally incompetent to face a trial.
Had he gone in front of a jury, Poste could well have been sent to prison.
How was the Zodiac Killer ‘identified’?
Gary Francis Poste is the Zodiac Killer, according to the Case Breakers – a group of more than 40 former police investigators, journalists and military intelligence officers.
The team said it had based its case on forensic evidence, photos found in Poste’s own darkroom and on some of the serial killer’s coded notes.
The forensic evidence proved Poste killed Cheri Jo Bates, the group claimed.
Bates was murdered by an unknown killer in 1966.
Those who have followed the Zodiac case closely believe her death was the work of the Zodiac Killer – although the San Francisco Chronicle has reported that this theory has been rejected by local police.
Poste has also been said to bear a resemblance to a 1969 police sketch of the Zodiac Killer as he had similar scars on his forehead.
And the letters of his name were found to change the meaning of the ciphers the serial killer had sent in letters to newspapers, suggesting Poste was the killer.
However, the Case Breakers’ findings have been dismissed by local police and the FBI, according to the San Francisco Chronicle.
The San Francisco office of the FBI told the newspaper that the Zodiac Killer case remained open.
On 20 November 2021, the Case Breakers followed up their claims by saying they had discovered a “goldmine” of evidence in California.
In a statement, the team said it had discovered that Poste had given away weaponry, including pistol parts, gunpowder and shell casings, to friends and relatives in the lead up to his death.
“Most of these peculiar ‘gifts’ have remained in basements and closets, untouched, ever since,” the Case Breakers claimed.
The team said it had sent this evidence to private forensic labs in three US states.
It also alleged Poste had at one time been the leader of a group of young men he had trained up to become what the Case Breakers described as “killing machines”.
The men, who were in their late teens and early twenties, were believed to have been known as “The Posse” and were said to have killed animals for fun, the New York Post reported.
What did the zodiac killer do?
The Zodiac Killer killed five people in the San Francisco area in the late 1960s and then sent taunting coded letters to local newspapers.
His victims were either shot or stabbed.
- David Faraday
- Betty Lou Jensen
- Darlene Ferrin
- Cecelia Shepard
- Paul Stine
Ferrin and Shepard’s partners – Michael Mageau and Bryan Hartnell – survived the attacks they were subjected to.
All the victims were young couples in their teens or early twenties – apart from Stine who was a 29-year-old taxi driver.
The killer has been linked to several other cold cases and claimed in one letter to have killed 37 people.
But this claim remains unproven.
The serial killer followed up each murder with letters and cryptograms to local newspapers.
These sometimes contained threats, including a plot to kill a busload of school children.
The letters all opened with the phrase “this is the Zodiac speaking” – spawning the Zodiac Killer moniker – and were typically signed off with what appeared to be the crosshairs of a gun.
The letters stopped appearing in 1970.
Speculation about the murderer’s identity has been rife ever since.
The police have only ever officially named one suspect in the case – convicted child molester Arthur Leigh Allen.
Allen was picked out of a police line-up by one of the Zodiac Killer’s attempted victims, and owned a watch carrying the crosshairs symbol.
He reportedly made a partial confession about carrying out the murders to a friend, but died of a heart attack in 1992 before a case could be built against him.
Another man, a former journalist named Richard Gaikowski, has also become an unofficial suspect among armchair investigators.
While Gaikowski had an alibi at the time, a recent documentary broadcast by RTE in Irelandquestioned its veracity.
There is a long-standing joke that prominent Republican senator Ted Cruz is the murderer – a claim he has played up to on Twitter through memes.
The Zodiac Killer has spawned many pop culture references, including the 1971 Clint Eastwood film Dirty Harry and 2007 Jake Gyllenhaal, Mark Ruffalo, Robert Downey Jr. vehicle Zodiac.
Paul Dano’s character in the latest incarnation of the Batman franchise, ‘The Batman’, is also believed to have been inspired by the serial killer.
What will Disney+ series The Most Dangerous Animal of All reveal?
While the most recent thinking has Gary Francis Poste nailed on as the Zodiac Killer, a series that’s coming to Disney+ in the UK and Ireland on 20 July argues a different person is the serial killer.
Based on a 2014 New York Times bestseller of the same name, The Most Dangerous Man of All is a four-part documentary series about a man who claims to have found strong evidence that the Zodiac Killer is his biological father.
Gary L. Stewart was given up for adoption as a child.
But when his birthmother first got in contact with him at the age of 39-years-old, a decade-long search for his father – Earl Van Best Jr. – uncovered evidence which appeared to line him up with the serial killer.