A 24-year-old man with a history of mental illness will be locked up for more than three decades for killing a mother and son who let him live in their rural Minnesota home.

William L. Hillman, of Frazee, Minn., was sentenced Tuesday in Otter Tail County District Court to a 51-year term for the April 2018 beatings of Denise McFadzen, 42, and Dalton McFadzen, 21, in their Gorman Township home north of Perham.

Judge Kevin Miller imposed consecutive 25½-year terms for each killing. With credit for time in jail since his arrest nearly three years ago, Hillman will serve more than 32 years in prison and the balance on supervised release.

In November, after reviewing reports from numerous psychiatric experts who examined Hillman, Miller rejected the defendant's mental illness defense and found him guilty.

The judge pointed to Hillman carrying out "some level of planning" before the killings and his understanding that he knew what he did "was morally wrong and illegal."

Denise McFadzen's body was outside the entrance to the home, while her son's body was in a bed. They had been beaten with a large pipe wrench, according to the charges.

"I'm sorry," Hillman said in a remote appearance at his sentencing, according to WDAY-TV in Fargo. "I would never do this in a million years if it wasn't for mental illness. … This just proves I can't live a normal life without my medication."

Hillman told authorities on the day of the killings that he had hadn't taken his medications for schizophrenia for five months, according to court records.

In nearby Cass County, court records there show that Hillman was ruled mentally ill in June 2016, soon after he punched his mother and threatened to kill her. He was committed to the Minnesota Security Hospital at St. Peter for treatment. That commitment ended in November 2017, according to a court filing.

Dr. Charles Chmielewski wrote in an evaluation leading to the ruling that Hillman was suffering from a "thought disorder [and] does pose a substantial likelihood of physical harm to others."

On the same day of the killings, according to court records, Hillman told a sheriff's detective that "all of a sudden … it was just they felt like Satan worshipers, and they just felt so weird, and it didn't feel safe, and honest to God I feel that house is evil."

Paul Walsh • 612-673-4482