As The Most Dangerous Animal Of All Revists The Zodiac Killer, Here’s What You Need To Know

In the late '60s and early '70s, the Zodiac Killer terrorized California, killing at least five people — although he is suspected in many more cases. But even though it's been over 50 years since he became national news, no one has ever been able to figure out who the Zodiac Killer actually was. There have been many theories over the decades, and one of the newest ones is gaining traction thanks to the new docuseries on FX and Hulu, The Most Dangerous Animal of All.

Based on the 2014 memoir of the same name, it tells the story of Gary Stewart, who believes that the Zodiac Killer is allegedly his biological father, Earl Van Best, Jr. who died in 1984, according to CNN. Per Business Insider, Stewart points to circumstantial evidence in his book like that his father allegedly looked like the sketch of the Zodiac killer (with a crew cut and glasses) and one of the murders happened nearby where Best was allegedly living at the time. CNN reported that Stewart also allegedly found his father's initials in the Zodiac's codes and ciphers that were sent to local newspapers, mocking law enforcement for not being able to find him.

CNN reported that the San Francisco Police Department said that it would look into any possible link, because the case was still an open investigation. However, SFGate later reported that they were unable to establish a connection. "We didn't kiss him off," said investigator, John Hennessy, the former San Francisco Police Department captain. "He was a very nice man, very well spoken. And I think he was sincere in his belief that his father was the Zodiac, but there wasn't enough to move quickly on. And the reality is that without hard evidence it’s hard to prove a case."

The reason that the Zodiac's identity has stayed a mystery for half a century is because he didn't leave any usable DNA at his crime scenes, according to another SFGate article. Or at least not any DNA that was collected and retained by investigators in the '60s and '70s. SFGate reported that in the early 2000s, investigators were able to establish a partial DNA profile. They used the traces of saliva on the stamps from the killer's coded messages to newspapers. But that was not enough to go on, as the partial profile could only rule suspects out, but not anyone in. A partial fingerprint found by police also proved to never be enough information to go on.

Additionally, the Zodiac's many coded messages sent to newspapers between 1969 and 1974 proved hard to crack, and some parts of the ciphers have never been fully figured out. If his identity is revealed in those codes, we don't know it. The case was so frustrating that the police department finally closed it in 2004, according to CBS News. "The case is being placed inactive," then-Lieutenant John Hennessey said. "Given the pressure of our existing caseload and the amount of cases that remain open at this time, we need to be most efficient at using our resources."

However, around 2007 when the Zodiac movie was released, the case was reopened and has remained so ever since. According to CNN, Gary Stewart is not the only person who has claimed to have been related to the Zodiac Killer. Like with Stewart, those claims have been investigated but also proved inconclusive.

If the FX docuseries turns up any new information, the SFPD will likely look into it. But don't count on this mystery being solved any time soon.