For decades, the infamous Zodiac Killer — who killed at least five people in California in the 1960s and claimed to have killed more than 30 — has never been identified, despite his letters to local media taunting police. 

But California detectives are hoping to use those letters against the killer by lifting genetic material and utilizing advances in DNA science and genealogy databases.

The Sacramento Bee reports that investigators in Vallejo have sent envelopes used by the suspected killer to a lab for advanced DNA analysis. Authorities plan to run the recovered DNA through online genealogy sites, and will attempt to identify the Zodiac Killer through familial connections.

Genealogy websites were used to identify the alleged Golden State Killer, who’s accused of committing a spate of murders and rapes in California in the 1970s and ’80s and was apprehended last year.

RELATED: ‘Golden State Killer’ Suspect Identified as Ex-Cop

Two people survived the Zodiac Killer’s attacks, providing police with detailed descriptions of their assailant.

His letters to local news outlets featured cryptograms, in which he called himself “Zodiac.” They were also signed with a cross over a circle.

He stopped writing the letters in the 1970s.

Police departments in San Francisco and Napa counties are also taking a fresh look at their evidence, believing it could lead to a break in the investigation, reports the San Francisco Chronicle.

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Detective Terry Poyser of the Vallejo Police told The Bee that DNA from saliva may be recovered from the envelopes. If that happens, and “we get a good profile, then you start tracking back,” Poyser said. “It really comes down to DNA. Without it, you have nothing. It’s a 50-years-old case.”

Results from the DNA analysis are expected back in the coming weeks.

Last April, police arrested Joseph James DeAngelo, 72, a former police officer, identifying him as the suspected Golden State Killer through genealogy websites.

RELATED: Golden State Killer: Behind the Years-Long Investigation

DeAngelo was charged with capital murder in four killings: The Feb. 2, 1978, slayings of Brian and Katie Maggiore and the March 1980 slayings of Lyman and Charlene Smith.

DeAngelo has yet to enter pleas to the charges, and remains in police custody without bail.

The next hearing in his case is set for April 10.

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  By Chris Harris