A 74-year-old Montana man has been sentenced to 15 years and six months in prison for killing his wife, his stepson, and his stepson’s girlfriend in a shocking triple murder.
The Crime
Michael Joseph Ackerman pleaded guilty in January 2026 to second-degree murder and use of a firearm during a crime of violence, according to federal court records. The murders took place in September 2025.
The victims were Ackerman’s wife of 35 years, 65-year-old Earlene Lucy Jones Ackerman; his stepson, 41-year-old Matthew Earl Black Thunder; and his stepson’s girlfriend, 35-year-old Winona “Nona Sioux” Longee.
The Plea Agreement
Ackerman’s guilty plea shortened the trial process. Prosecutors had requested a sentence of 27 years and six months, while the defense suggested a lighter term. The court ultimately sentenced Ackerman to 15 years and six months, slightly higher than the defense request but well below the prosecution’s recommendation.
The plea deal allowed him to plead guilty to just two counts, not taking the full sentencing range into account.
What Happened on the Day of the Murders
According to the government’s report, Ackerman had been using methamphetamine at home and began believing his family was “setting him up.” He took a Smith & Wesson 9mm pistol and shot his wife twice in the head.
He then walked into the room where his stepson and his girlfriend were sleeping and shot them both.
A call to the Yellowstone County Sheriff’s Office came from one of Ackerman’s adopted sons, reporting that Ackerman was driving after committing the murders. Deputies arrested Ackerman at home and recorded his confession. Tribal law enforcement later discovered the victims at the residence.
Defense Statement
Ackerman’s public defender described the case as “a conundrum.” The defense highlighted his “almost zero criminal history” and the influence 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 said. “There appears to be no motive—this was a senseless act of violence fueled by methamphetamine and made easier by the use of a firearm.”
The defense also noted Ackerman’s personality, stating he “presents as a very warm person” and remained polite and respectful throughout the legal process.
Life After Prison
Ackerman was working as a plumber at the time of the murders and had shown interest in running for tribal government office. After serving his sentence, he will be subject to five years of supervised release.
