LOS ANGELES (AP) — A California man prosecutors called a serial killer was convicted Thursday of raping and killing two women in the 1980s after investigators linked him to DNA evidence, prosecutors said.

Horace Van Vaultz Jr., 67, was found guilty of first-degree murder with the special circumstance allegations that the crimes involved multiple murders, rape and sodomy, the Los Angeles County district attorney’s office said in a statement.

Vaultz, a former Bakersfield resident, has been jailed since his 2019 arrest. He could face life in prison without the possibility of parole when he is sentenced next month.

Vaultz was convicted of killing 22-year-old Mary Duggan in 1986. Her body was found in the trunk of her car in a parking lot in the Los Angeles suburb of Burbank. He also was convicted of the 1981 killing of 20-year-old Selena Keough, whose body was found under bushes near an apartment building in Montclair, in San Bernardino County. Both were strangled.

The cases went cold for decades until they were linked to Vaultz using investigative genetic genealogy, in which genealogical websites are used to identify potential relatives of a suspect based on DNA collected at a crime scene.

It was the first criminal case in LA County to use the procedure, the DA’s office said.

At his trial, the prosecution argued that Vaultz was a sexually motivated serial killer. The defense argued that he had consensual sex with the women and someone else killed them. Vaultz described himself as a “”swinger” and said he couldn’t remember meeting the victims.

Prosecutors also said a recent re-examination of evidence showed a DNA link between Vaultz and a third killing in Ventura County, KNBC-TV reported.

Janna Rowe, 25, was strangled and left on a trash pile. Vaultz was acquitted of her death in 1988, before DNA evidence was used at trial, and cannot be retried.

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