Wisconsin cold case: How investigators made an arrest after 50 years

Authorities explained on Monday how they were able to arrest a suspect 50 years after the murder of a Minneapolis woman who was killed hitchhiking across Wisconsin.

Latest developments

Last week, the Dunn County Sheriff's Office announced they had arrested 84-year-old Jon Keith Miller of Owatonna in the killing. He is charged with first-degree murder. 

His arrest followed another re-examination of DNA evidence using genealogical testing. When confronted with the DNA evidence, the criminal complaint states that Miller admitted to picking up Mary K. Schlais while she was hitchhiking and stabbing her to death.

Background

Schlais, 25, was found dead near the intersection of 408th Avenue and 990th Street in Spring Brook Township, Wisconsin, on Feb. 15, 1974, a rural area eight miles west of Eau Claire.

Schlais was hitchhiking from Minneapolis to an art show in Chicago. Three witnesses saw a suspect and a vehicle that were believed to be connected to Schlais' killing. 

"In 1974 it wasn’t that unusual for somebody to hitchhike their way from Minneapolis to Chicago. But it’s stories like this that is the reason we don’t let our kids do it anymore," said Dunn County Sheriff Kevin Bygd at a press conference Friday. "This was a very bright young lady who had a very bright future ahead of her, and her life was taken away from her way too young."

Over the years after the case, as DNA technology evolved, the case was re-examined, but investigators were unable to identify a suspect until now.

How did they solve the case?

Among the evidence found at the scene was a stocking hat. At the time of the murder, before DNA investigative technology existed, the hat was a piece of the puzzle. But, investigators likely didn't realize how crucial it would be.

"Investigators at that time knew the hat would be important to the investigation, but probably not in the way we were able to utilize evidence from this hat nearly 50 years later," explained Dunn County Sergeant Jason Stalker. "Prior to DNA technology, the stocking hat was only able to be utilized for human hair comparisons."

But, years later, investigators were able to pull a partial DNA sample from the hat but were unable to identify a suspect. However, more recently, investigators were able to turn over the DNA sample to genealogists at Ramapo College, which cracked open the case.

"Using the partial male profile developed years earlier, through their work, a family lineage was identified, and new leads were developed," said Sgt. Stalker.

Using the family tree, investigators went through, one by one, working to identify a suspect. But, ultimately, they cleared each known family member in the lineage. That led investigators to conclude there had been an adoption in the family. With help from Miller's biological relatives, investigators were able to identify Miller as the suspect.

"The family tree research in this case was very complicated, and it took over a year for our investigative genetic genealogy to bear fruit," said Cairenn Binder, a genealogy investigator at Ramapo.