Who was the Zodiac Killer as investigators believe they've uncovered his identity?

The Zodiac Killer terrorized California in the 1960s and now his identity could finally be revealed

Zodiac Killer wanted poster
(Image credit: Photo by Sacramento Bee photo illustration/TNS/ Sipa US / Alamy Stock Photo)

The Zodiac Killer’s true identity has been eluding investigators since his reign of terror in the late 1960s which saw him commit a series of horrific murders in California. Now, decades later, they might have found the answer.  

Many years have now passed since the infamous Zodiac Killer terrorized the population of Northern California. However, the impact of his appalling crimes is very much still felt and the question of who he was has continued to plague investigators since the 1960s. Unlike other serial killers such as The Serpent’s Charles Sobraj and Pam Hupp, who Renée Zellweger is set to play in The Thing About Pam, the Zodiac Killer was not caught. Though that didn’t stop independent investigative group The Case Breakers from looking into the matter again.

Now they’ve announced a major discovery as they revealed their belief that after all this time, they’ve finally uncovered the Zodiac Killer’s identity and posed a significant new theory. 

But who was the Zodiac Killer, when was he active and what documentaries were made about him? 

Who was the Zodiac Killer?

The Zodiac Killer was a notorious serial killer who carried out a series of brutal murders in the San Francisco area in the late 1960s. In a move reminiscent of Victorian serial killer Jack the Ripper, the Zodiac Killer is understood to have sent police, The San Francisco Chronicle and other local papers highly cryptic letters and cyphers, as well as bloodstained clothing. 

Whilst his identity was never revealed at the time of the murders, the volunteer investigative group, the Case Breakers, claim they have found a new suspect. The group are made up of former law enforcement officers and journalists and have now alleged that Gary Poste, who is thought to have passed away in 2018, could have been the Zodiac Killer. 


Zodiac Killer sent this cryptogram after committing his crimes

(Image credit: Photo by Bettmann Archive/Getty Images)

The Case Breakers have suggested that this theory is based on multiple factors, including a supposed similarity between a police sketch of the Zodiac Killer from 1969 and photos they’d found of Mr Poste. As reported by The Independent, they’ve claimed that reported scars on Mr Poste’s forehead matched marks shown on the police sketch, though this hasn’t been confirmed. 

They also say they have uncovered a possible anagram in one of the cyphers left by the Zodiac Killer in his letters to the police that reveal their suspect’s name. 

However, according to The San Francisco Chronicle, the FBI is not convinced by the Case Breakers’ new theory, reporting that the agency’s San Francisco office declared in a statement, “The Zodiac killer case remains open. We have no new information to share at the moment.” 

Whilst the publication added that the San Francisco Police Department “echoed the statement” given by the FBI. With so many conflicting theories as to who the Zodiac Killer could be emerging over the years and law enforcement not assured about the Case Breakers’ recent claims, it might be many years yet before the case is officially declared solved.  

When was the Zodiac Killer active? 

The Zodiac Killer was active between 1968 and 1969 in Northern California. As reported by The New York Post, the first known murders believed to have been carried out by the serial killer took place in December 1968. A couple were tragically shot dead in a car in Benica and following this, another couple were shot in Vallejo just six months later in July 1969, with only the man surviving. 

Chicago Police Lt. John Lewison, at his Chicago home, March 25, 2011, spreads out copies of a map, codes and other clues left behind by a notorious killer

Chicago Police Lt. John Lewison spreads out copies of a map, codes and other clues left behind as he tries to solve the cryptograms left by the notorious Zodiac killer.

(Image credit: Antonio Perez/Chicago Tribune/Tribune News Service via Getty Images)

Later on that same year, a third couple are understood to have been stabbed, with the man surviving the attack and a cab driver was also shot in San Francisco. Throughout his reign of terror, the Zodiac Killer sent chilling notes to local publications and the police, as well as cyphers which he reportedly claimed would reveal his identity if solved.

Despite his series of brutal murders and all his sinister messages, however, the Zodiac Killer suddenly went silent, with his identity remaining a mystery and no definitive cause ever determined for the lack of further murders. Today the case remains one of the United State’s most infamous unsolved murder cases.  

How many people did the Zodiac Killer murder? 

The Zodiac Killer has had five murders and two attempted murders officially attributed to him, though in one of his taunting letters, he reportedly declared he’d killed as many as 37 people. One murder that has been alleged by some to be another Zodiac killing was the murder of Cheri Jo Bates, who was killed in Riverside in 1966. 

The Case Breakers’ have supported this theory, though according to The San Francisco Chronicle, this possibility has already been debunked by police. 

Zodiac Killer wanted poster

(Image credit: Photo by Sacramento Bee photo illustration/TNS/ Sipa US / Alamy Stock Photo)

The publication reports that Riverside Police Officer Ryan Railsback told them, “Is there a chance that (the Case Breakers suspect) killed Cheri Jo Bates? No. If you read what they (the Case Breakers) put out, it’s all circumstantial evidence. It’s not a whole lot.”

Meanwhile, he suggested that in August his department announced that they’d worked with the FBI to disprove a letter and other evidence that suggested Cheri was a Zodiac Killer victim, offering instead a $50,000 reward for tips leading to her actual killer. Sadly, after so many years, just like the Zodiac Killer case, Cheri’s murder case currently remains unsolved. 

Documentaries about the Zodiac Killer

Given the appalling nature of his crimes and the ongoing speculation regarding his real identity, the Zodiac Killer has often been the subject of documentaries over the years. The Most Dangerous Animal of All is a four-part TV miniseries that focuses on Gary L. Stewart, who suspects that the twisted serial killer is actually his biological father after years of research. 

And this isn’t the only documentary about the Zodiac Killer to delve into the infamous case. Back in 2017, the History Channel released their own 5-part miniseries, The Hunt for the Zodiac Killer, which looked into the evidence so far in an attempt to get to the truth. They even brought in expert code breakers to help decipher the cyphers and notes sent by the killer. 

Whilst for those living in the US who are looking to learn more about the Zodiac Killer investigation, The Zodiac Killer Documentary: The Unknown Killer is also available to watch on Amazon Prime Video. 

As well as multiple documentaries over the years, the Zodiac Killer has inspired films, including The Zodiac, Curse of The Zodiac and, perhaps most prominently, Zodiac. This 2007 film directed by David Fincher features Hollywood stars Jake Gyllenhaal, Mark Ruffalo and Robert Downey Jr. 

Just like the documentaries, the chilling film depicts the manhunt to identify and bring the Zodiac Killer to justice for his crimes, ending with the declaration that the case remains open.

Emma Shacklock
Emma Shacklock

Emma is a Senior Lifestyle Writer with five years experience working in digital publishing, ranging from book publishing to magazines. She currently looks after all things Lifestyle for Woman&Home, GoodToKnow and My Imperfect Life.


Before she joined Future Publishing, Emma graduated from the University of Warwick with a Bachelor of Arts degree in English and Comparative Literary Studies. After leaving education, she started out her publishing career in the world of books, working as a Publisher for an independent digital publisher specializing in back-list and debut commercial fiction novels. With a huge book list and a passion for bringing the best stories to the broadest audience possible, Emma filled her spare time with reading the latest best-sellers and catching up on hit adaptations.


In 2017 she joined TI Media as a fiction writing coordinator on Woman’s Weekly and Woman’s Weekly Fiction as part of the features team. From here, she used her love of books, working to bring short stories to our dedicated readers and began writing for the books pages of Woman, Woman’s Own and Woman&Home, as well as online features ranging from genre round-ups to travel pieces for womanandhome.com. 


After honing her skills, Emma branched out online in 2020 when Future gave her the opportunity to focus on digital-first. When she’s not writing about the next big lifestyle trend, she enjoys cooking, long walks and watching as many crime dramas as she can!