Michael Ackerman (Yellowstone County Detention Facility).
A Montana man in his seventies has been sentenced to a relatively brief term in prison following the tragic deaths of his wife, stepson, and his stepson’s girlfriend. The events unfolded in September 2025, leading to a legal resolution that concluded this week.
Michael Joseph Ackerman, aged 74, admitted his guilt in January to charges of second-degree murder and using a firearm during a violent crime, as per federal court records. This plea marked a significant turning point in the case, averting a potentially lengthy trial process.
The victims of this grievous incident were Earlene Lucy Jones Ackerman, 65, Matthew Earl Black Thunder, 41, and Winona “Nona Sioux” Longee, 35. The plea agreement allowed Ackerman to admit to two counts related to the triple murder, which was driven by drug use.
This week, Ackerman received a sentence of 15 years and six months, a decision that falls short of the 27 years and six months proposed by prosecutors. However, the punishment does exceed the term suggested by the defense, which highlighted Ackerman’s minimal criminal record and methamphetamine use in their arguments.
The defense characterized the case as “a conundrum,” reflecting on the complexities of Ackerman’s background and the circumstances leading to the crime. The plea agreement did not stipulate sentencing specifics, focusing instead on securing Ackerman’s guilty plea for the tragic events that unfolded.
The defendant’s public defender called the case “a conundrum” in the defense’s own sentencing memo – noting Ackerman’s “almost zero criminal history” and his use of methamphetamine.
“The victims include Michael’s wife of 35 years, a stepson he raised from an early age and his stepson’s girlfriend,” the defense memo reads. “There appears to be no motive, instead this was a senseless act of violence fueled by methamphetamine and made easier by the use of a firearm.”
On Sept. 14, 2025, the Yellowstone County Sheriff’s Office received a phone call from one of Ackerman’s adopted sons, according to the Billings Gazette. The defendant was driving after killing three people, the caller told law enforcement.
The government’s memo describes the murders, at length:
On that day, Ackerman was using methamphetamine in his home. He came to believe his family was “setting him up.” He picked up his Smith & Wesson 9mm pistol and shot his wife twice in the head. He heard her son and his girlfriend moving around in the next room, but when he walked into the room they were sleeping. He shot them both as they slept.
Deputies detained Ackerman at home and recorded his confession. Then, tribal law enforcement discovered the victims at the residence.
At the time of the slayings, the defendant was working as a plumber and had expressed interest in running for a tribal government office.
“To make this case all the more perplexing,” the defense sentencing recommendation goes on, “Michael J. presents as a very warm person. Throughout this entire legal process, Michael J. has been polite and respectful.”
If and when Ackerman makes it out of federal prison, he will be subject to five years of supervised release.
