When Minneapolis' Mary Schlais was found stabbed to death in a rural Wisconsin snowbank in February 1974, investigators had no idea who killed her, and the case went unsolved for decades.

But on Thursday, the Dunn County Sheriff's Office in Wisconsin announced it made an arrest in the cold case and 84-year-old Jon Miller was taken into custody in Owatonna. The identification was made possible in part due to the Sheriff's Office's collaboration with a team of genetic genealogists at Ramapo College in New Jersey.

The 84-year-old was charged with first-degree murder on Thursday in Dunn County Circuit Court.

Dunn County Sheriff Kevin Bygd said he was glad to be able to deliver the news to Schlais' family that a suspect was arrested and charged.

"To finally put a bow on it and have someone in custody for it, who is still alive after 50 years, it's exciting," he said Friday.

Schlais was 25 at the time of her death and was attempting to hitchhike from Minneapolis to Chicago for an art show. Schlais was picked up by Miller somewhere in the Twin Cities area, Bygd said, before the woman was stabbed and killed. Miller was a Pine City resident at the time, the sheriff noted.

An eyewitness at the time said they saw someone throw Schlais' body out of the car before driving away.

A hat was left along with the victim's body at the scene, Bygd said, which allowed investigators to analyze the DNA of the hair and skin cells found inside it. At the time there was no sufficient technology to process that DNA, but in the subsequent decades it became possible.

"It was a lot of extensive research with the DNA link and the genealogy that was done," the sheriff said. "[The college] was able to steer us in the right direction of the family."

The investigation also included numerous tips, leads and interviews conducted by multiple agencies over the decades it remained unsolved.

Sheriff's Office investigators traveled to Wyoming to track down a family member of Miller who voluntarily gave his own DNA to match it to the suspect, Bygd said. When the officers traveled to Owatonna to arrest Miller, he admitted the killing, according to the sheriff.

He remains in custody in Minnesota but he will soon be extradited to Wisconsin, Bygd said.