Justice Finally Served: Arrest and Conviction in the 50 Year Old Cold Case Murder of Mary Schlais
In February 1974, the body of 25-year-old Mary Schlais was found stabbed to death on a Wisconsin roadside. Five decades later, DNA clues left at the scene helped identify and convict her killer
Background
On the afternoon of February 15, 1974, the body of 25-year-old Mary Kathleen Schlais of Minneapolis, Minnesota, was found face down in the snow near a roadside in rural Spring Brook Township in Dunn County, Wisconsin.
She had been stabbed more than a dozen times and had a broken nose and other injuries. Despite the frigid temperature, when investigators arrived on the scene, her body was still warm. This meant that the murder had occurred very recently, possibly within the hour.
The police had received a call from a man who had observed what appeared to be two people fighting. When he returned to the area, he saw a body partially buried in the snow. Though he was able to provide a partial description of the suspect and his car, sadly, it would take another five decades for the killer to finally be unmasked.
Mary Schlais
Mary Kathleen Schlais was born on November 11, 1949, and grew up in Champlin, Minnesota, alongside her two brothers. They all attended Anoka High School, where Mary first showed her artistic talents.
After high school, her passion for art and creativity took her to the University of Minnesota, where she graduated with honors in art, earning scholarships and recognition along the way. She continued her studies, working toward a master’s degree at the same institution.
Mary's classmates and professors at university remembered her as bright, driven, and full of life. On her walls hung self-created sculptures and paintings that focused on women's experiences, including work displayed at the Women's Institute for Social Change at the YCA.
Her love for travel and languages led her to study abroad. She became fluent in German and Danish and was also learning Japanese.
Mary also had a strong sense of adventure. Like many young people in the early '70s, she embraced the freedom of the era. She was known to hitchhike around the Midwest, often combining travel with her artistic pursuits.
February 15, 1974
On the morning of February 15, 1974, Mary left her Uptown Minneapolis apartment at about 10:30 a.m. She carried a small cardboard sign that read "Madison" and planned to hitchhike to an art show in Chicago.
She wore a tan fur-lined coat over a maroon turtleneck and blue jeans and carried her purse. Her roommate, Judith, saw her leave that morning.
Less than three hours later, around 1:30 p.m., a local man out walking his dog on a dead-end road near Elk Creek Lake in Spring Brook Township saw two people struggling as if fighting each other. When he returned, he found the body of a young woman partially buried in the snow.
He immediately called the sheriff's office in the Township of Spring Brook, Dunn County, Wisconsin, about 90 miles from Minneapolis. Although her body was partially covered with snow, investigators determined that she was still warm to the touch when they found her. This told them that the murder had just happened recently, perhaps less than an hour before the body was discovered.
The autopsy revealed she had been stabbed at least 13 to 15 times. The wounds were concentrated in her back, chest, and neck, and she had defensive cuts on her hands and fingers, suggesting that she had tried to fight back.
Her nose was broken, likely from being struck during the attack. The medical examiner later confirmed that Mary had died from blood loss resulting from multiple stab wounds and blunt force trauma.
Next to her body was a black and orange stocking cap. It didn’t belong to Mary, and no one knew who it belonged to at the time. Investigators collected hairs from the hat as evidence. There were also some tire tracks, but the snow had made them nearly impossible to trace.
Investigation
From the start, investigators had some key eyewitness information. A local man driving by at the time recounted seeing a gold or tan compact car stopped beside the road near the time of the murder. He reported seeing a man throw what looked like a body out of the vehicle into the ditch where Mary's body was later found.
Several other witnesses came forward with similar descriptions of a white man, about 5'8" to 6 feet tall, with light brown or hazel eyes and a thick mustache. He was estimated to be in his late 20s to mid-30s.
Though the descriptions varied slightly, the recurring description of a gold-colored compact car and a mustached man stuck out. Despite the leads, investigators could not immediately identify the driver as no license plate had been seen.
Over the next several months, the Dunn County Sheriff’s Office and other agencies aggressively worked the case. They followed up on more than 400 leads, chasing tips from across the U.S. and even Canada. Posters were made, articles ran in local newspapers, and family and friends were interviewed multiple times.
During the 1980s and 90s, investigators even explored connections to known serial killers, like Randall Woodfield, the “I-5 Killer,” who was a former football player who had murdered several women along the West Coast. Woodfield’s timeline and victim profile made him a potential match, but DNA testing later ruled him out.
As technology improved, so did the tools available to cold case investigators. In 2009, more than three decades after her death, Mary's body was exhumed so that advanced DNA testing could be done. However, no conclusive evidence was found.
Breakthrough
After decades of frustration and dead ends, Mary’s case got a second life thanks to powerful advancements in forensic genetic genealogy. In the spring of 2023, Dunn County detectives partnered with the Investigative Genetic Genealogy (IGG) Center at Ramapo College, New Jersey, who specialize in using DNA and family trees to identify unknown suspects in cold cases.
Investigators extracted a partial male DNA profile from the hairs in the cap and submitted it to the IGG team. They began to build a family tree, which was a reverse search that started with matches and worked backward to find a likely source.
Throughout late 2023 and early 2024, the team traced potential family lines. That led them first to a man in Wyoming and then another in Michigan. Each man was interviewed and submitted a DNA sample, which ultimately ruled them out.
Investigators then realized that the culprit may have been adopted, which complicated the search.
Suspect Identified
The breakthrough came in November 2024, after months of painstaking work, when investigators connected the DNA dots to an 84-year-old man from Owatonna, Minnesota, named Jon Keith Miller.
Investigators had first traced the DNA profile to Miller’s daughter, and after interviewing her, she agreed to provide a DNA sample for testing. The testing concluded that her biological father matched the DNA profile of the hair fibers taken from the wool cap left at the crime scene.
Born on May 2, 1940, Miller had lived in Owatonna, Minnesota, for years, about two hours from the crime scene. At the time of the murder in 1974, he was 33 years old, matching the physical description given by witnesses.
On November 7, 2024, members of the Dunn County Sheriff's Office interviewed Miller at his home. He initially denied any knowledge of or involvement in the murder of Mary Schlais.
Confession
When detectives confronted Miller with DNA evidence linking him to the orange-and-black stocking cap found at the scene, he broke his silence and confessed to what happened that cold February day in 1974.
He told investigators that on February 15, 1974, he picked up Mary Schlais, who was hitchhiking in Minneapolis. The two were driving near Dunn County, Wisconsin when he made a sexual advance. When Mary refused, Miller said he grabbed a knife stashed in the car's sun visor and stabbed her in the back, continuing the attack until she collapsed and stopped moving.
He described how Mary fought back, using her hands to shield herself, which left her with several defensive wounds when she was overpowered. Afterward, he dragged her body off the road and attempted to hide it in a snowbank. But when another car appeared, he panicked, abandoned the body, and fled.
Miller admitted the cap was his. He said he hadn’t realized he had lost it until he was shown the crime scene photos during his interview. He also confessed to disposing of the knife after the event, throwing it into a swampy area near his home in Minnesota.
Throughout his confession, Miller offered no apology and very little remorse. He said, "Maybe I'm cold … cold-blooded". He told the story plainly, confirming what police had suspected for decades but could never prove until DNA evidence and genealogy filled in the missing pieces.
Arrest and Legal Proceedings
Following his confession, the 84-year-old Miller was arrested and taken into custody. Miller was formally charged with first-degree intentional homicide. He was held on a one-million-dollar bond and later extradited to Wisconsin to face trial.
In March 2025, Miller decided to enter a no-contest plea to the charge of first-degree intentional homicide. The plea allowed both sides to avoid a lengthy trial and provided a swift resolution for a case that had haunted a family and community for half a century.
Under the terms of the plea deal, Miller was convicted of first-degree murder and sentenced to life in prison. In addition to the life sentence, Miller was ordered to pay $2,200 in restitution to Mary Schlais’s family. He was also required to reimburse over $480 for extradition expenses, though that was noted separately. The family later donated some of the restitution money to support cold-case efforts at Ramapo College.
Aftermath
When Don Schlais, Mary’s younger brother, heard the news that her killer had finally been identified and arrested in November 2024, his reaction wasn’t dramatic. After nearly 50 years of silence, grief, and uncertainty, Don simply said, “I think I’m too old to feel much of anything anymore.” It was a heavy statement, not of indifference but of emotional exhaustion.
For Nina Schlais, Mary’s niece, who was born after Mary’s death but carried her aunt’s legacy across generations, the resolution of the case was deeply emotional for her. At the sentencing hearing, she said, “Justice truly has no time limit, and we can all breathe again now.”
Sources:
“Mary Kathleen Schlais Murder.” Crime Timeline, 26 May 2025, crimetimelines.com/mary-kathleen-schlais-murder/.
Kremer, Rich. “DNA from Hat Found in 1974 Leads to Arrest in 50-Year-Old Dunn County Murder Case.” WPR, 8 Nov. 2024, www.wpr.org/news/dna-hat-1974-cold-murder-case-arrest-dunn-county-murder-case.
Gawker, Refugee. “R/Truecrimediscussion on Reddit: Hitchhiker Mary K Schlais.” Hitchhiker Mary K Schlais Killed in 1974. Fifty Years Later, Cops Arrested Her Killer, 2025,www.reddit.com/r/TrueCrimeDiscussion/comments/1gndecm/hitchhiker_mary_k_schlais_was_killed_in_1974/.
Torres, Lesley Cosme. “Young Woman’s Hitchhiking Trip Turned into a Tragedy: How Police Solved the Crime Decades Later.” People.Com, PEOPLE, 31 Mar. 2025, https://people.com/young-womans-hitchhiking-trip-turned-into-tragedy-how-police-solved-crime-decades-later-11706250
Incredible story. Amazing how technology and justice finally caught up with this man, albeit 50 years too late.
Numbers 32:23c
“…be sure your sin will find you out.”