A documentary with “never before seen evidence” revealing the dark secrets of a mystery serial killer in the 1960s – named the Zodiac Killer – has just dropped on Netflix.

It became one of the most chilling and notorious cases as the so-called Zodiac Killer taunted press and police with letters claiming responsibility for 37 murders in Northern California.

However even after extensive investigations, nobody was never prosecuted due to insufficient evidence, making it one of the most chilling unsolved cases. 

The lead suspect is named as Arthur Leigh Allen, and in the new documentary, David and Connie Seawater who knew Arthur well admitted they thought he was the Zodiac Killer.

It’s not the first time Allen has been suspected of being the Zodiac Killer by those close to him, as he was reported to the police by friend Don Cheney shortly after the killings commenced, suggesting he fit the killer’s profile.

Cheney claimed Allen expressed a desire to murder young couples using a gun with a torch attached to the barrel, which aligned with media reports about the ongoing Zodiac murders.

He also alleged that the convicted felon Allen, who had been fired from his position as a teacher at Valley Springs Elementary School in 1968 and charged with molesting students, intended to write to the police under the name Zodiac.

In September 1972, investigators obtained a search warrant for Allen’s home, trailer and vehicles in Santa Rosa, with police records indicating they were looking for a pair of 9mm handguns used in the murders, along with ammunition.

Investigators also sought trophies that the alleged killer might have taken from his victims, including a bloodied shirt, which the killer had been sending in small pieces.

However when police arrived at his home Allen was missing, raising suspicions that he had been notified of their visit.

To add to the amounting suspicion, in July 1992, a survivor of the Zodiac Killer’s attacks identified Allen in a line-up as the man who shot him.

Despite claiming to be responsible for 37 murders, investigators agree The Zodiac Killer was linked to seven confirmed assault victims in the San Francisco Bay Area between 1968 and 1969. Five died and two survived.

The first victims were teenagers David Arthur Faraday, 17, and Betty Lou Jensen, 16, who were shot and killed on December 20 1968, on Lake Herman Road in Benicia.

In July 1969, 19-year-old Michael Renault Mageau and 22-year-old Darlene Elizabeth Ferrin were shot in the parking lot of Blue Rock Springs Park in Vallejo. Mageau survived but Ferrin was pronounced dead at Kaiser Foundation Hospital.

The Zodiac Killer’s final victim, 29-year-old Paul Lee Stine, was shot and killed on 11 October 11 1969 in the Presidio Heights neighborhood of San Francisco.

The Zodiac Killer got their name from the symbols and letters used in his communication with the media and police, referring to themselves as “Zodiac” and including a symbol resembling a crosshair.

The case was labelled as inactive by authorities in 2004. The documentary is now available for streaming on Netflix.