Nine Of The Most Likely Zodiac Killer Suspects And The Disturbing Stories Behind Them

Published July 20, 2026
Updated July 21, 2026

Ross Sullivan: A Notorious Suspect In The Death Of Cheri Jo Bates

Was Ross Sullivan The Zodiac Killer

TwitterSome believe that Ross Sullivan has a strong link to possible Zodiac victim Cheri Jo Bates.

There are a couple of reasons why some believe that Ross Sullivan was the Zodiac Killer. But the most compelling has to do with the murder of Cheri Jo Bates, who some consider a potential Zodiac victim, in 1966.

Then, on Halloween, Bates’ body was discovered on the Riverside City College campus, where the 18-year-old had just started her freshman year. According to Voigt’s Zodiac Killer website, she had been beaten and stabbed.

Sullivan was one of the original suspects in Bates’ murder. He worked at the campus library, which was close to where the body was found, and several of his coworkers at the library remembered that he made them uneasy. He even briefly disappeared after Bates’ death.

Cheri Jo Bates

TwitterCheri Jo Bates was just 18 when she was murdered, possibly by the Zodiac Killer.

Though Bates isn’t considered an official Zodiac victim, her murder has struck many as eerily similar to the Zodiac Killer’s crimes. Local newspapers received letters after Bates’ death with details only her killer would know, and that these letters bore a resemblance to the Zodiac Killer’s letters (including word usage and misspellings).

What’s more, Sullivan’s possible connection to Bates isn’t the only reason why some think that he’s a convincing Zodiac Killer suspect. Sullivan studied cryptology, wore army boots (similar to prints that were found at a Zodiac crime scene), and with his thick spectacles, he bore a strong resemblance to the Zodiac Killer.

Today, however, Sullivan’s whereabouts are unknown. And since Bates is not officially considered a Zodiac victim by the police — though she is by some experts like Voigt and the Case Breakers — her murder might not have anything to do with the Zodiac Killer or his mysterious identity.

Who Was The Zodiac Killer? Why Some Think Richard Marshall Was The Infamous Murderer

Was Richard Marshall The Zodiac Killer

YouTubeRichard Marshall appeared to have multiple things in common with the Zodiac Killer.

Between 1969 and 1974, the Zodiac Killer sent over 20 letters, usually to local newspapers in Northern California. And certain details that he mentioned in the notes have led some to believe that the Zodiac Killer was movie projectionist and ham radio operator Richard Marshall.

According to History, the Zodiac Killer often dropped hints about his life and interests in his letters, and many of them aligned perfectly with Marshall’s. Both liked the film The Red Phantom, both apparently lived in basement apartments, and both liked felt-tip pens and unusually-sized paper.

“I must have a double floating around,” Marshall said during a 1989 TV interview, in which he also professed his innocence. “The characteristics you just mentioned fit me almost to a T.”

Richard Marshall In 1989

YouTubeRichard Marshall admitted that he shared interests with the Zodiac but denied being the killer.

As Voigt explains on his Zodiac Killer website, Marshall first emerged as a Zodiac Killer suspect in 1976 after he made “suspicious” comments over his ham radio. But some investigators don’t think he’s a strong suspect.

“Marshall makes good reading but not a very good suspect in my estimation,” said Napa County sheriff’s detective Ken Narlow.

Voigt also acknowledges that detectives visited Marshall at a care facility shortly before his death in 2008, and they somehow determined that he was not the murderer. But they didn’t — to the best of Voigt’s knowledge — test Marshall’s DNA. “Therefore, in my opinion,” Voigt wrote on his site, “Marshall remains a viable Zodiac suspect.”

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Kaleena Fraga
author
A senior staff writer for All That's Interesting since 2021 and co-host of the History Uncovered Podcast, Kaleena Fraga graduated with a dual degree in American History and French Language and Literature from Oberlin College. She previously ran the presidential history blog History First, and has had work published in The Washington Post, Gastro Obscura, and elsewhere. She has published more than 1,200 pieces on topics including history and archaeology. She is based in Brooklyn, New York.
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Jaclyn Anglis
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Based in Queens, New York, Jaclyn Anglis is the senior managing editor at All That's Interesting, where she has worked since 2019. She holds a Master's degree in journalism from the City University of New York and a dual Bachelor's degree in English writing and history from DePauw University. In a career that spans 11 years, she has also worked with the New York Daily News, Bustle, and Bauer Xcel Media. Her interests include American history, true crime, modern history, and science.
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Fraga, Kaleena. "Nine Of The Most Likely Zodiac Killer Suspects And The Disturbing Stories Behind Them." AllThatsInteresting.com, July 20, 2026, https://allthatsinteresting.com/who-was-the-zodiac-killer. Accessed July 24, 2026.