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 one suspect, Arthur Leigh Allen, they were never able to piece together enough evidence to arrest him. Allen died in 1992, and the mystery of the Zodiac killer continues to haunt him. Now, people who say they knew Allen as children are revealing in a new documentary series that he confessed to being the Zodiac killer to them, drugging them as children and perhaps even taking them on killing sprees.

In This is the zodiac speaking, David and Connie Seawater, a three-part documentary coming to Netflix on October 23, say that in the 1960s they would take weekend trips with Allen, a local school teacher who was like a father to them. They believe Allen was responsible for murders in the area during those trips that occurred prior to 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 messages in code and demanded that they be published on the front page of San Francisco newspapers, threatening to kill more people if they did 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 anyone.

This is the zodiac speaking includes interviews with the Seawater children, former students of Allen – plus their home videos and letters from him – along with background on the case of 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 is to transport viewers to a bygone era of California before scaring them. “First, I want the audience to be swept up in the nostalgia of carefree, technology-free California,” he says. ‘And then I want them to be very scared. Afraid for the victims and their families who were stalked and abused in the most cruel way. I don’t want the audience to experience this unpredictable, lurking evil as something far away and impossible to understand, but in the most relatable, innocent and terrifying way: as children. Like a close-knit group of siblings who loved Allen as a teacher and trusted him as a member of their family. And probably still.”

Here’s a look at the most revealing quotes from the docu-series 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 bonded with their mother Phyllis and became a fixture at family dinners. Allen was an avid diver and he took the children on field trips, such as clam digging, and to movie theaters.

Allen was a beloved teacher at the school, known for dancing and singing along to classroom music such as the Kingston Trio’s “Tom Dooley” and the Gilbert and Sullivan soundtrack for The Mikado.

A former student, Darin Alvord, describes how Allen taught them to decipher codes and thought his teacher was just trying to teach them different ways of communicating.

Other former students remember the way he called the girls in his class “my beauties.”

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 Zeewater children believe they were close.

They remember Allen coming to their home at the end of the 1963 school year to see if they wanted to watch him dive. When they arrived at Tajiguas Beach, they say Allen immediately took off. The kids were allowed to play alone, and then Allen came rushing back, huffing and puffing, with red stuff on his hands, loading the kids into the car and running away with them. The documentary flashes to the headlines about the deaths of Domingo and Edward at the same time, as the Seawaters believe Allen may have been behind the double murder.

On October 28, 1966, when David Seawater was a sophomore in high school and Connie was a freshman, Allen stopped by their home to take them to a race track in Riverside. On October 30, Connie found her brother David fast asleep at the motel and could not be woken. Then she remembers taking Allen for a ride and he put his hand on her pedal pushers. She remembers returning to the motel, drinking some juice and then falling into a deep sleep, unable to remember anything except Allen leading them to the car on October 31. On October 30, 1966, a woman named Cheri Jo Bates was found dead, and the Seawaters believe Allen was the one behind it, although the case was never solved.

People who think Allen is the Zodiac killer point out how the Zodiac killings stopped when he was arrested for child abuse in 1974. He spent three years in prison and then served five years in prison until 1982.

The confessions of the suspected Zodiac killer

In the docuseries, Connie says she now believes Allen hinted 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 asked 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 sobbed on the phone as he confessed to drugging them as children and abusing his sister Connie. When he asked Allen if he was the Zodiac killer, he says Allen admitted he was. Allen died on August 26, 1992, at the age of 58.

After seeing the 2007 film Zodiac-starring Jake Gyllenhaal and Robert Downey Jr. like San Francisco Chronicle employees of the case and Mark Ruffalo as a detective – they were struck by actor John Carroll Lynch, who played Arthur Leigh Allen in the film. They thought he looked exactly like the real Allen, and then realized that before the murders, they had been to all the locations where Zodiac murders took place. “There was so much in that movie that was eerily familiar,” says Connie This is the zodiac speaking.

The Seawater children say in the series that their mother Phyllis never believed that Allen could be the Zodiac killer or a child molester. After she passed away on April 23, 2017, her children found a box containing numerous letters she exchanged with Phyllis in which he talked about the zodiac, and these are included in the series. “Every time someone spoke to me about the police I jumped,” he wrote in one. “Seeing a murder head would make my palms sweat,” he wrote in another. And in the letter the Seawater Children find the most revealing, he wrote, ‘the most dangerous is when I almost decide to confess.’

Graysmith says that Allen was likely attracted to the Seawater children and their family because he always wanted a partner and a family, but instead lived with his mother in a basement, noting that the Zodiac victims murderer ‘were almost always married people. My theory is: they are happy and he is not.”