The Zodiac killer is one of the most notorious killers of all time, but has never been caught. Now, a family who knew the prime suspect Arthur Leigh Allen whave come forward for the first time in the Netflix documentary This Is the Zodiac Speaking to reveal shocking new information in the case.

Investigators have since drawn connections between Allen's classroom activities and the Zodiac's infamous communications. One of the Zodiac's letters specifically quoted lyrics from "I've Got a Little List," and the serial killer was known for purposely misspelling common words.

Arthur Leigh Allen is the prime suspect in the unsolved Zodiac Killer crimes, though his fate may prevent justice from ever being served.

Explore the new evidence in the Zodiac Killer case as the Netflix documentary "This Is the Zodiac Speaking" examines Arthur Leigh Allen's role as a suspect.

Netflix’s documentary ‘This is the Zodiac Speaking’ includes interviews with the Seawater siblings, who grew up knowing and interacting with Arthur Leigh Allen. They were familiar with him as both a teacher and a friend of their mother.

People who knew Arthur Leigh Allen as children say he confessed, drugged them, and brought them to the sites of Zodiac killer murders

The Zodiac Killer’s identity has baffled investigators and the public for decades, with numerous suspects examined by authorities and web sleuths alike, but no definitive answer has emerged. Netflix’s docuseries ‘This is the Zodiac Speaking’ delves into the case,

Netflix’s This is the Zodiac Speaking focuses on Arthur Leigh Allen, but eight other men have been accused of being the killer.

The Zodiac Killer was connected to several murders in Northern California during the 1960s, earning his cryptic name by sending taunting letters to local newspapers that threatened killing sprees if they weren't published.