SPRING HILL, Fla. (AP) — Investigators in Florida confirm that a 17-year-old teen who went missing in 1980 was the victim of a serial killer now serving a life sentence in California.

Hernando County Sheriff’s investigators said Wednesday that they identified the remains of Theresa Caroline Fillingim as the third of four bodies unearthed at a junkyard north of Tampa in 1981.

A tipster led investigators to the junkyard back then, following publicity from Billy Mansfield Jr.’s murder trial in California. It took a Virginia lab using new technology to build a profile that helped identify the missing teen through a match of her sister’s DNA.

The fourth victim has still not been identified.