84-year-old arrested in 1974 cold case murder after he's ID'd with genetic genealogy

A 84-year-old man has been arrested for a cold case murder from 50 years ago after he was linked to the crime via genetic genealogy, authorities said Monday.

On Feb. 15, 1974, Mary Schlais was found stabbed to death on a road in Dunn County, Wisconsin, about 75 miles east of Minneapolis, the Dunn County Sheriff’s Office said.

Schlais, an accomplished artist, was believed to be hitchhiking from her hometown of Minneapolis to an art show in Chicago when she was killed, authorities said.

Decades went by without an arrest.

A key piece of evidence -- a stocking cap -- was left at the crime scene, but the hairs on the hat had no matches in the Combined DNA Index System, the law enforcement database known as CODIS, according to the sheriff's office.

Then, last year, the Dunn County Sheriff's Office partnered with Ramapo College of New Jersey to try to solve the case using investigative genetic genealogy.

With genetic genealogy, an unknown killer's DNA from a crime scene can be identified through his or her family members, who voluntarily submit their DNA to genealogy databases. This allows police to create a much larger family tree than using law enforcement databases like CODIS.

Around the fall of 2023, a possible family line for the suspect was identified, authorities said.

This January, an investigation began into an individual possibly related to the suspect, authorities said, and in May, police interviewed that person at their home in Wyoming.

Investigators determined that individual was not the suspect, but he did lead police to another possible suspect -- his cousin in Michigan, authorities said. The man in Michigan was also interviewed and determined to not be the suspect, authorities said, which "exhausted any known male family members in this family lineage."

Authorities said they then considered the possibility that their mystery suspect was adopted, and therefore unknown to the people on his own family tree.

This fall, investigators spoke to another relative who agreed to use their genetic profile to help, authorities said. That relative led to the suspect, 84-year-old Jon Miller, whose DNA was linked to the crime scene, authorities said.

Miller's DNA was found to be a match on Nov. 4 -- which would've been Schlais' 76th birthday, police noted.

Miller, who had been adopted, was arrested for murder on Thursday at his home in Owatonna, Minnesota, authorities said. Miller confirmed his involvement in the murder when he was confronted with the evidence against him, according to sheriff's officials.

"He did inform us that as soon as he had opened the door, he knew why we were there," authorities said.