MENOMONIE, Wis. — "If you worked for this agency for any amount of time, you knew about Mary Schlais and her case," Sgt. Jason Stocker said at the beginning of a press conference held at the Dunn Co. Sheriff's Office in Menomonie, Wisc.
The 50-year-old mystery of who killed Mary Schais stumped Dunn County Sheriff's investigators since the day they found her stabbed to death on the side of a rural road.
But they say the mystery ended with a confession from 84-year-old Jon Keith Miller.
"He did inform us that as soon as he opened the door, he knew why we were there," said Dunn Co. Investigator Dan Westland.
What brought Dunn County investigators to Miller's door in Owatonna was a new investigative method that has been used to solve cold cases across the country since it was famously used to catch the Golden State Killer in 2018 — investigative genetic genealogy (IGG).
"Investigative genetic genealogy, or IGG, uses genetic genealogical information to reverse-engineer a family tree from an unknown individual's DNA," said David Gurney, a Bemidji native who leads the IGG Center at Ramapo College in New Jersey.
The IGG Center offers pro bono services to help police departments solve cold cases for free — as well as teaching students how to do that work.
The Ramapo College team started helping the Dunn County Sheriff's Office after cold calling them upon finding Mary's case online.
Dunn County provided them a DNA profile they say they developed from a stocking cap Mary Schlais' killer left at the crime scene.
From there, the genealogists say the process is similar to how an adopted person might set out to use DNA family tree websites to find biological relatives.
But investigators aren't allowed to use Ancestry.com or "23 And Me." which have millions of DNA profiles uploaded — they can only use two, much smaller databases, from FamilytreeDNA.com and GEDmatch.
"Depending on the complexity of the case, how close the matches are, whether there is adoption in the family tree, a case can be solved in an hour or it can take thousands and thousands of hours and many years," said Cairenn Binder, assistant director of Ramapo College's IGG Center.
Finding Jon Keith Miller wasn't easy, the genealogists say, because it turns out he was adopted. The two cousins in Wyoming and Michigan they first pointed Dunn County officials toward didn't even know about him.
Then, they linked a different family located in Minnesota with Miller in mind.
"It's a lead we turn over to law enforcement, like someone calling into a tip line. It's then up to law enforcement to confirm or refute that lead, using more targeted DNA comparisons," Gurney said.
Mary's family at the Dunn County press conference hugged and thanked the New Jersey team for helping provide them with answers that, with the age of the case, seemed to grow less and less likely each year.
"I think my primary reaction is just happiness that there will hopefully be justice for Mary in this case," Gurney said.
The Ramapo College IGG Center also recently helped exonerate an innocent man after 25 years in prison. Their work helped determine David Bintz and Robert Bintz were innocent after they traced the DNA from the actual killer to William Joseph Hendricks, a man with prior convictions for similar crimes.
Miller has now been moved from the jail in Owatonna, where he was arrested, to Dunn County, where he will make his first appearance in court very soon.