PORT WASHINGTON, Wis. (AP) — Authorities in eastern Wisconsin say they know who killed an 18-year-old woman in 1984.

The Ozaukee County Sheriff’s Office on Tuesday announced a suspect they believe killed Traci Hammerberg. Hammerberg was found fatally bludgeoned and partially naked in the driveway of a Town of Grafton home nearly 35 years ago. Her killer was never found.

But authorities used DNA evidence and forensic genealogy to identify her killer as Phillip Cross, who was 21 at the time. Cross died of a drug overdose in 2012.

Authorities linked the suspect through a DNA match of the suspect’s second cousin.

Hammerberg attended Port Washington High School. Police said at the time she had been at a party the night she disappeared.

Cross left work at a factory that night when their paths crossed.