Police in Wisconsin closed a cold case of the rape and murder of an 18-year-old girl in the 1980s after 35 years by using the FBI’s forensic genealogy technology, a report said Tuesday.

Philip Cross, who died of a drug overdose in 2012, was identified as the killer of 18-year-old Traci Hammerberg, who was murdered in the town of Grafton on Dec. 15, 1984, the Journal Sentinel reported.

Before her slaying, Hammerberg went to a party where she and her friends drank and smoked marijuana, according to the report.

She then left and started a more than three-mile walk home, but was found dead in a snowy driveway, the Journal Sentinel reported.

Police recovered blood from underneath Hammerberg’s fingernails and semen at the scene. They used the evidence to develop a DNA profile of her alleged killer, according to the report.

In 2019, police decided to use forensic genealogy crack the case and reached out to the Los Angeles FBI team who helped solve the Golden State Killer cold case with the technology.

Police used the technology to track any distant second-cousin of the attacker, which led them to Cross.

They linked the DNA to Cross’s, which was on file after he died of a drug overdose in 2012.

Investigators credited the genetic genealogy technology with helping crack the case.