DNA from a tissue left in a trash can led authorities to arrest a former California police officer suspected of being the Golden State Killer, according to warrants released Friday.

The documents detail the case pieced together by Sacramento County sheriff’s investigators to arrest 72-year-old Joseph DeAngelo.

He is suspected of committing at least a dozen killings and roughly 50 rapes in the 1970s and 80s, making him one of California’s most elusive serial killers.

Investigators zeroed in on DeAngelo by using genealogical websites to identify potential relatives of the killer based on DNA collected at a crime scene.

The DNA from a semen sample was collected after a double murder in Ventura County in 1980, according to the warrants.

After identifying DeAngelo as a suspect, investigators followed him to a store in April and took a swab from the handle of a door he used. That sample didn’t immediately lead to an arrest.

Three days later, investigators collected trash from cans left outside DeAngelo’s home in Citrus Heights, California. A piece of tissue plucked from the trash proved to be the piece of evidence they needed to obtain an arrest warrant, according to the documents.

The Associated Press and other news outlets fought to make the documents public over objections from DeAngelo’s public defenders. Sacramento County Superior Court Judge Michael Sweet agreed to release 123 pages of records.

Victims’ identities and some details about the investigation were redacted at the request of prosecutors.

[Featured image: Joseph DeAngelo/José Luis Villegas, The Sacramento Bee via AP, Pool]