HOUGHTON COUNTY, Mich. (WZMQ) – A Wisconsin man has taken a plea agreement for his role in the 2023 death of his grandfather in Hancock Township.
On December 18, 2025, Jacob Kempainen pled guilty to second-degree murder in Houghton County’s 12th Circuit Court. In exchange for his plea, the open murder and conspiracy charges against him and the firearm charge against him will be dismissed. There is a sentencing agreement that the minimum sentence must not exceed 15 years in the Michigan Department of Corrections.
The agreement requires Jacob to cooperate with investigators and testify truthfully in the trial of his co-defendant, Margaret.
“This plea offer was made after lengthy discussions with investigators, a careful evaluation of the evidence, and in consultation with multiple family members of the victim, Alvin Kempainen”, said Houghton County Prosecutor Dan Helmer. “Unfortunately, although Jacob invoked his Miranda rights prior to questioning, Iowa police did not honor his request, and his entire statement was suppressed by the Court. The entire case then hinged on the testimony of his then-juvenile sister, which presented concerns for both myself and the lead detective.”
Helmer went on to say that a recent Michigan Supreme Court decision also factored into plea negotiations while the case was pending.
“The Michigan Supreme Court recently found, inexplicably, that automatic life without parole sentences for 20-year-olds are unconstitutional,” he said. “Jacob was 20 at the time of the murder, and that decision took away a lot of the leverage my office had in plea negotiations. Another strong factor in this plea offer was doing whatever I can to secure a conviction against Jacob’s mother, Margaret Kempainen, for her role in this horrible crime – no plea offer has been extended to her.”
Despite the murder happening exactly two years ago, both defendants have had their cases repeatedly delayed. At another hearing on December 18, Margaret Kempainen’s jury trial—scheduled for January 2026—was once again adjourned to allow her attorney to appeal recent evidentiary rulings in the case to the Michigan Court of Appeals.
“These evidentiary motions were not filed until 15 months after the preliminary examination,” said Helmer. “This delay, yet another in a long history of delays, was at the request of Mrs. Kempainen’s attorney and while I certainly can understand it from a legal perspective, was a decision by the judge, not by agreement. It is frustrating to have these evidentiary issues in front of the Court so long after the case was bound over.”
Helmer added, “The Houghton County Sheriff’s Office and I share the frustration of the family, and I am sure the general public, in how long this case is taking to proceed to trial. I am, and have been, ready, willing, and able to present this case to a jury and seek justice for Alvin Kempainen and his family.”
Jacob Kempainen will be sentenced at a later date by 12th Circuit Judge Brittany Bulleit.
