Joseph DeAngelo

(AP) — Prosecutors have added another murder charge against a California serial killing suspect, boosting the number of victims to 13.

Tulare County District Attorney Tim Ward said Monday that suspect Joseph DeAngelo was charged with first-degree murder in the killing of Claude Snelling, who was shot while stopping the kidnapping of his 16-year-old daughter in Visalia.

The community college teacher was shot in 1975.

Visalia Police Chief Jason Salazar said detectives are also confident DeAngelo is a burglar known as the Visalia Ransacker, who struck more than 100 homes in the 1970s in the farming community about 40 miles (64 kilometers) south of Fresno.

DeAngelo worked as a police officer in nearby Exeter at the time. He is also alleged to be the murderer known as the Golden State Killer.

The 72-year-old DeAngelo was previously charged in 12 killings throughout the state.

Authorities arrested him in April based on DNA evidence.