These siblings are convinced their former teacher was the Zodiac Killer. Here’s why

More than 50 years after the Zodiac Killer went on a murder spree in California, law enforcement officials and amateur sleuths alike are still captivated by the case.

Despite years of investigation, the identity of the Zodiac Killer remains a mystery.

A new three-part Netflix docuseries, “This is the Zodiac Speaking,” shares one family’s experiences with Arthur Leigh Allen, the only person police have ever officially named as a suspect in the Zodiac murders. 

The documentary explores the family’s close connection to Allen in the 1960s, and reveals a shocking confession Allen allegedly made shortly before his death. 

TODAY.com has reached out to the San Francisco Police Department for comment on the investigation and if allegations included in the documentary have led to movement in the case.

Keep reading to learn more about the Zodiac Killer, and what was uncovered in Netflix’s new documentary about his infamous unsolved crimes.

Who was the Zodiac Killer?

The Zodiac Killer, whose identity has never been confirmed, was a serial murderer who terrorized the San Francisco Bay Area in 1968 and 1969. He was never caught.

Five murders have been officially attributed to the Zodiac Killer, who often targeted young couples, per the San Francisco Chronicle. 

The Zodiac Killer was known for sending cryptic letters about his crimes to newspapers and police, per the San Francisco Chronicle. These letters often included ciphers and coded messages. Many included what became his trademark symbol, a circle with cross hair symbols, and began with the words, “This is the Zodiac speaking…” 

In 2014, writer Gary Best said that his biological father, Earl Van Best Jr., was the Zodiac Killer, laying out his claims in a book, “The Most Dangerous Animal of All: Searching for my Father … and Finding the Zodiac Killer.” 

Despite multiple theories arising over the years, police have only ever named one suspect in the Zodiac Killer case: Arthur Leigh Allen, who died in 1992. 

Who was Arthur Leigh Allen, and how does he play into the Zodiac Killer investigation?

Arthur Leigh Allen remains the only named suspect in the Zodiac Killer investigation. 

Allen, who died in 1992 at age 58, was a Navy veteran, former schoolteacher and convicted sex offender. 

Vallejo police Detective Terry Poyser described Allen as “an extremely intelligent but a deviant dude,” per the Sacramento Bee.

Allen arose as a suspect in the Zodiac killings as early as 1971, when one of his former friends, Don Cheney, went to the police with concerns about threatening statements Allen had made when they had last seen each other in 1969. 

Cheney’s interview with the police is included in the Netflix documentary.  

Cheney, who had known Allen for years, said in a 1971 police interview that he remembered Allen talking about “shooting tires on the school bus and picking the little darlings off as they come bouncing out of the bus.”

This phrase echoed a sentence from one of the Zodiac Killer’s letters, which talked about the killer’s desire to “just shoot out the front tire and then pick off the kiddies as they come bouncing out.” 

“That phrase about ‘picking the little darlings off,’ I remembered that, and that’s what forced me to go to the police,” Cheney said in his 1971 interview, the audio of which was shared in the Netflix documentary.

Following their interview with Cheney, police visited Allen at his workplace. The documentary played the audio recording of an interview San Francisco Police Department inspector David Toschi, who worked on the Zodiac case, did with true crime author Robert Graysmith, whose work inspired David Fincher’s movie “Zodiac.”   

Toschi noticed Allen was wearing a Zodiac watch emblazoned with a crossed-over circle — the same symbol the Zodiac Killer used to sign some of his letters. 

After this encounter with Allen, authorities obtained a warrant to search his trailer. They discovered hunting knives inside, as well as a freezer full of dead hamsters, squirrels and birds, Toschi said.

However, Toschi said they did not find any hard evidence linking Allen to the Zodiac murders. 

“We came away a little depressed. I thought we would find more,” Toschi told Graysmith.

In 1974, Allen crossed paths with police once again when he was arrested and charged with child molestation. Allen spent about two years at Atascadero State Hospital, which seeks to treat pedophiles.

Authorities were never able to build a strong enough case against him, though they looked into him.

“Mr. Allen was a very, very good suspect,” Toschi reportedly said, per Allen’s obituary in the San Francisco Chronicle in 1992. “We looked into Mr. Allen very closely.”

In 1991, police searched Allen’s home in Vallejo as part of a follow-up to the unsolved investigation and “found some writings, some pipe bombs, some illegal weapons,’’ Vallejo Police Captain Roy Conway told the San Francisco Chronicle in 1992. “None of it was sufficient to make an arrest for him being the Zodiac.’’

Allen died of a heart attack in 1992. He repeatedly denied being the Zodiac Killer in letters, as well as in media interviews, according to the documentary.

“He was trying everything he could to absolve himself,” Allen’s friend Glenn Rinehart told the Vallejo Times Herald in 2007. “He did the best to tell his side of the story.” 

In 2002, San Francisco homicide detectives said they were testing new DNA evidence from letter envelopes that could have cleared Allen. However, authorities ultimately said these tests were inconclusive, according to the San Francisco Chronicle. 

“Arthur Leigh Allen does not match the partial DNA fingerprint developed from bona fide Zodiac letters,” inspector Kelly Carroll told the San Francisco Chronicle. 

Who are the Seawaters, and what do they say in a new documentary?

Netflix’s new three-part documentary, “This Is the Zodiac Speaking,” focuses on the accounts of members of the Seawater family, who knew Allen beginning in the early 1960s.

In 1961, Allen was a schoolteacher who formed a special relationship with single mother Phyllis Seawater and her six children — and especially with her three eldest kids, Connie, David and Don. Many of the children go on the record in the documentary. TODAY.com has reached out to Connie and David Seawater for comment.

Connie Seawater describes Allen, who was her teacher, as being “burly, smiley and friendly.” 

In the documentary, the elder Seawater siblings say they had fond early memories of Allen, saying he became like a father figure to them, taking them on excursions and giving them gifts.

The Seawaters recall the details of one trip Allen took them on, which, looking back, seems sinister. In the summer of 1963, the siblings say Allen drove them to Tajiguas Point, a remote area of beach in Santa Barbara. They say he asked the kids to wait in the car while he went down to the beach, and he was gone for up to an hour. 

When he returned to the car, Connie Seawater, who was 9 or 10 at the time, says Allen had something red on his hands, but says she didn’t understand at the time what that could mean. She also remembers Allen was carrying something that he placed in the trunk, and that he drove away from the beach in a panic. 

This trip aligns with the timing and locations of murders of Robert Domingos, 18, and his fiancée, Linda Edwards, 17, who were shot on June 4, 1963, per the Santa Barbara Independent.

Domingos and Edwards’ murders have never been conclusively tied to the Zodiac Killer, but according to the documentary, authorities believe the details of their murders — a young couple being targeted in a remote area near a body of water — bore trademarks of the Zodiac Killer’s style.

For years, the Seawater siblings did not believe their beloved former teacher, Mr. Allen, could have anything to do with the Zodiac Killings. 

However, in 1992, David Seawater says he had a life-altering phone call with Allen. Seawater says, in the documentary, that Allen admitted to having drugged David and his siblings when they were kids. 

David Seawater also says Allen admitted to molesting Connie Seawater.

“There were periods where we were groggy, we had no explanation for it. I realized then exactly what he was doing, and how he was doing it,” David Seawater says in the documentary. 

He then says he asked Allen, “‘Were you the Zodiac?’”

“There was deathly silence. I didn’t hear anything for a second, and I hear this gasping noise, and he was just crying,” Seawater says. “He collected himself enough and he came back on in a real weak voice and goes, ‘Yes, it was me.’” 

Seawater went to the police following this phone call, but says the detective he spoke to said there was nothing they could do.

TODAY.com has reached out to the San Francisco Police Department for comment about the phone call.

The family connected more dots years later after watching the 2007 movie “Zodiac,” which stars John Carroll Lynch as Allen and Mark Ruffalo as Toschi, one of the lead investigators in the case.

When they saw the movie, the Seawater siblings noticed eerie connections between trips they had taken with Allen as kids, and the timings and locations of the Zodiac Killer’s murders.

“We started researching things and realized we had been to all the murder sites before the murders,” David Seawater says in the documentary.

“We were kids when we went with him, so we didn’t connect Mr. Allen to the murder sites until we saw them in the movie,” Connie Seawater says in the documentary. 

Connie Seawater also says she had an epiphany when she saw the wetsuit hood Allen’s character wears in the movie, realizing that she had helped the real-life Allen make a very similar hood. 

“When we started connecting the dots, I started seeing too many coincidences to be coincidences,” she says.