The rape and murder of an 18-year-old girl in Wisconsin 35 years ago has finally been solved after police compared DNA evidence to a genealogy database.

Traci Hammerberg was found raped, beaten and strangled to death on a snow-covered driveway in Saukville, north of Milwaukee, on December 15, 1984.

Her brutal death went unsolved for three decades until the Ozaukee County Sheriff's Office revealed on Tuesday that DNA databases had helped lead them to her killer.

Authorities have revealed Philip Cross, who died in 2012, was the person responsible for murdering Traci Hammerberg in Milwaukee back in 1984 after comparing DNA to a genealogy database

Authorities are now saying that Philip Cross, who was 21 at the time, was responsible for Hammerberg's slaying.

Cross died of a drug overdose in 2012.

Despite authorities creating a DNA profile at the time from the semen found on Hammerberg's body, they were never able to identify a suspect.

They started looking at genealogy databases in March to see if that original DNA profile matched with any of the killer's relatives.

Investigators said the DNA profile matched with a potential second cousin.

Traci Hammerberg was found raped, beaten and strangled to death on a snow-covered driveway in Saukville, north of Milwaukee, on December 15, 1984 after a night out with friends

Her brutal death went unsolved for three decades until the Ozaukee County Sheriff's Office revealed on Tuesday that DNA databases had helped lead them to her killer

They started creating a family tree based on the second cousin's relatives and narrowed down the suspects.

Cross was identified as a possible suspect in August.

The original DNA profile was then matched to DNA obtained from Cross' autopsy.

The sheriff's office said Cross would have been working night shifts in the area around the time the victim was killed.

Hammerberg had been out drinking with friends the night she died and investigators believe she accepted a ride from Cross when he was on his way home from work.

Forensic genealogy is the same method that helped authorities find a suspect in the notorious Golden State Killer case.