TThe Zodiac Killer is one of the most infamous unsolved serial killer cases of all time. He terrorized people in the Bay Area in the late 1960s, and although police named a suspect, Arthur Leigh Allen, they never managed to cobble together enough evidence to arrest him. Allen died in 1992 and the mystery of the Zodiac Killer continues to haunt him. Now people who claim to have known Allen as children reveal in a new documentary series that he confessed to them about being the Zodiac Killer, drugged them as children and may even have taken them to murders.

In This is the zodiac speaking, David and Connie Seawater, a three-part documentary coming to Netflix on October 23, recount that in the 1960s they took weekend trips with Allen, a local schoolteacher who was like a father to them. They believe Allen was responsible for nearby murders on the trips that preceded the Zodiac murders that terrorized San Francisco in the late 1960s.

The Zodiac Killer murdered at least five victims between December 1968 and October 1969. The killer wrote several coded messages and demanded that they be published on the front page of San Francisco newspapers, threatening to kill more people if they were not. At one point, the killer threatened to blow up a school bus full of children. And yet police said they never had enough evidence to arrest a person.

This is the zodiac speaking Includes interviews with the Seawater children, Allen's former students – as well as their home videos and letters from him – as well as background information on the case from Robert Graysmith, the journalist whose book Zodiac inspired the 2007 film of the same name.

This is the zodiac speaking Co-director Ari Mark says his intention behind the series was to transport viewers to a bygone era of California before scaring them. “First, I want the audience to be drawn into the nostalgia of carefree, technology-free California,” he says. “And then I want them to be very afraid. Fear for the victims and their families, who were persecuted and abused in the most cruel ways. I don't want the audience to experience this unpredictable, lurking evil as something distant and incomprehensible, but in the most relatable, innocent and frightening way – as a child. As a close-knit group of siblings who loved Allen as a teacher and trusted him as a member of their family. And they probably still do.”

Here's a look at the docuseries' most revealing statements and how they could shed light on the unsolved case of the Zodiac Killer.

Arthur Leigh Allen before he was the suspected Zodiac Killer

When David Seawater, Connie Seawater and their younger brother Don Seawater met Allen in the early 1960s, their father was in a mental institution. He became friends with her mother, Phyllis, and became a fixture at family dinners. Allen was an avid diver and took the children on excursions, such as shell hunting and to the movies.

Allen was a popular school teacher who was known for dancing and singing in class to music such as the Kingston Trio's “Tom Dooley” and the Gilbert and Sullivan soundtrack The Mikado.

A former student, Darin Alvord, describes how Allen taught them how to decipher codes, thinking his teacher just wanted to teach them different ways to communicate.

Other former students remember him calling the girls in his class “my beautiful one.”

Excursions that were followed by murders

The deaths of Robert Domingos, 18, and Linda Edwards, 17, on June 4, 1963, are not officially linked to the Zodiac Killer, but the Seawater children believe they were nearby.

They remember Allen coming to their house at the end of the 1963 school year to see if they wanted to watch him dive. When they arrived at Tajiguas Beach, Allen reportedly ran away immediately. The kids had to play alone, and then Allen came back huffing and puffing with red stuff on his hands, loaded the kids into the car and sped off with them. The documentary makes headlines about the simultaneous deaths of Domingo and Edward, as the Seawaters believe Allen may be behind the double murder.

On October 28, 1966, when David Seawater was a sophomore in high school and Connie was a freshman, Allen showed up at their house to take them to a racetrack in Riverside. On October 30, Connie found her brother David fast asleep in the motel and could not be awakened. She then remembers a car ride with Allen where he put his hand on her pedals. She remembers returning to the motel, drinking some juice and then falling into a deep sleep and not remembering anything except Allen walking her to the car on October 31st. On October 30, 1966, a woman named Cheri Jo Bates was found dead and the Seawaters believe Allen was behind it, although the case was never solved.

People who believe Allen was the Zodiac Killer point out that the Zodiac murders stopped when he was arrested for child molestation in 1974. He spent three years in prison and then served five years on felony probation until 1982.

The Confessions of the Suspected Zodiac Killer

In the docu-series, Connie says she now believes Allen hinted that he was the Zodiac Killer. She stayed in touch with Allen and even introduced him to her son. She remembers sailing with Allen in 1991 and asking him if he was the Zodiac Killer. He said if he told her he would have to kill her. But “I thought it was a big joke,” Connie says in the series.

David says he got a more direct answer from Allen. In 1992, his mother told him to call Allen because his health was rapidly deteriorating. She always stood by Allen, despite speculation that he was the Zodiac Killer. David says Allen cried on the phone as he confessed that he drugged them as children and abused his sister Connie. When he then asked Allen if he was the Zodiac Killer, he says that Allen admitted as much. Allen died on August 26, 1992 at the age of 58.

After watching the 2007 film zodiacwith Jake Gyllenhaal and Robert Downey Jr. as San Francisco chronicle Employees of the case and Mark Ruffalo as a detective – they were impressed by the actor John Carroll Lynch, who played Arthur Leigh Allen in the film. They thought he looked just like the real Allen, then realized that before the murders they had been to all the places where Zodiac murders had taken place. “A lot of things in this film seemed incredibly familiar,” says Connie This is the zodiac speaking.

The Seawater children say in the series that their mother Phyllis never believed Allen could be the Zodiac Killer or a child molester. After her death on April 23, 2017, her children found a box containing countless letters she had exchanged with Phyllis in which he talked about the zodiac. Excerpts from them can be found in the series. “Every time someone mentioned the police to me, I cringe,” he wrote in one. “If I saw a headline about a murder my palms would sweat,” he wrote in another. And in the letter that the Seawater children find most revealing, he wrote: “The most dangerous thing was when I almost decided to confess.”

Graysmith says Allen was probably drawn to the Seawater children and their family because he had always wanted a partner and a family. Instead, he lived in a basement with his mother and noted that the Zodiac Killer's victims were “almost always married people.” My theory is: They’re happy and he’s not.”