A Wisconsin man will serve a minimum of 15 years in Michigan state prison for his role in the 2023 murder of his grandfather at the victim’s Hancock Township home.
Jacob Kempainen, 22, of Hartland, Wisconsin, appeared before Houghton County 12th Circuit Court Judge Brittney Bulleit during his sentencing hearing Monday. Kempainen received a plea agreement in December 2025 in exchange for his testimony against his mother, Margaret Kempainen, who faces trial for the murder of Alvin Kempainen.
On Dec. 19, 2023, Alvin Kempainen was killed at his Hancock Township home by Jacob and Margaret Kempainen. Margaret was in the home with Jacob when Alvin was killed, according to court records. After the shooting, the pair and Jacob’s sister Kathleen fled the scene. Margaret and Jacob were later arrested in Iowa, while Kathleen was released because she was a minor at the time of the incident.
The sentencing hearing was originally scheduled for March but was delayed after severe weather closed the courthouse.
Several members of the Kempainen and O’Brien families traveled to the courthouse to attend the hearing in person, while others delivered remarks over Zoom.
“My brother should be held accountable for what he did,” said Jacob’s sister, Kathleen Kempainen. “But I believe he was also a victim.”
Kempainen’s attorney, David Gemignani, spoke at length during his closing argument about signs of mental illness Jacob displayed before the incident. He referenced results from Jacob’s counseling at the University of Minnesota in fall 2023, explaining that Jacob had shown signs of depressive disorder, social anxiety and passive dependence in November 2023.
Gemignani referred to a period before Dec. 19, 2023, when Margaret, Jacob and Kathleen were traveling together.
“Jacob and his sister are arriving up in Hancock Township in one vehicle. His mother is in another vehicle,” Gemignani said. “Jacob’s driving. He’s paying attention to the road. They are already at the opinion that grandpa is dead. Because as I briefed, when they were out in Colorado, his sister gets this message from the spirits, from God, from whoever, that grandpa’s dead and the spirits have gotten him.”
Gemignani continued, describing how Jacob had heard stories from his sister about their father being evil and involved in abuse and the occult.
“When they first met up in Wisconsin, at the La Quinta Inn, Jacob was scheduled to go home that weekend, and this is all disclosed on him while he is in a vulnerable state of mind,” Gemignani said.
Family members shared the devastating impact of receiving news of Alvin’s death. Alvin’s grandson, David O’Brien, read two statements — one for himself and one for his mother, Jannett O’Brien, who could not attend the hearing. Several family members in their victim statements requested the court impose a maximum life sentence.
“The worst news I have ever received in my life occurred December 19th, 2023,” O’Brien read from his mother’s statement. “Unable to make contact with my dad, I was anxiously awaiting word from him. I answered a call from my sister. She said sobbing to me, ‘They killed him.’ They, meaning my brother’s family — his son, Jacob, and his mother and his sister, who had been missing for over 10 days. They ambushed him in his living room, and Jacob shot him twice.”
The statement continued: “I can only imagine the terror and the confusion he must have felt to have the grandson he loved, and had just spent the week of Thanksgiving with, do this to him. I cannot erase these horrible thoughts from my mind. The brain must make sense of this horrible scenario, but there is no sense to be made, and it just causes more pain and suffering…”
Another grandson, Jeff O’Brien, described the lasting trauma of the crime.
“His death took place one week before Christmas, and that was the worst Christmas of my life,” Jeff O’Brien said. “For years now I have lost sleep and had nightmares about this crime. I frequently ask myself why Jacob did this? I still to this day do not understand the why. The most I understand is they were seeking shelter, but my grandfather would have never denied food or shelter to family in need…”
Jacob’s father, Allen Kempainen, also shared his feelings of loss in the context of losing both his father and, in a sense, his son.
“I am Allen Kempainen, and am in a position I never thought I would be in,” he said. “I am a victim, the son of the deceased. I am the father of the accused. My father was a special person, a person I looked to for guidance, for support, and who I gave all the support I could in the last few years he was alive, especially after mom passed…”
Judge Bulleit delivered Jacob a 15-year minimum sentence in recognition of his plea agreement and willingness to testify against Margaret Kempainen.
“I reviewed the pre-sentence investigation report on more than one occasion. I reviewed the numerous documents provided on more than one occasion. I listened closely to the arguments and victim impact statements presented today and have taken them all into account when making my decision,” Bulleit said. “I would like to thank the family of the victim for their courage to speak about the impact this has had on their lives.”
Jacob Kempainen was sentenced on second-degree homicide charges and could serve up to 50 years. A felony firearm charge was dismissed as part of the plea agreement. He has been credited with 837 days already served, accounting for his time in the Houghton County Jail.
Margaret Kempainen’s case has no new court date in Houghton County. Her case is currently held up in the Michigan Court of Appeals. Her attorney, Anthony Ruiz, filed motions to appeal denials by Judge Bulleit to suppress statements made to law enforcement at the time of her arrest and a motion for discovery regarding the counseling sessions of her daughter, Kathleen Kempainen, who was a minor at the time of the incident.
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