BILLINGS, MONT. — Michael Joseph Ackerman, 74, has been sentenced to 15 years and six months in federal prison for the September 2025 killings of his wife, stepson, and stepson’s girlfriend in Yellowstone County.
The Killings
On September 14, 2025, Ackerman used a Smith & Wesson 9mm pistol to shoot his wife, Earlene Lucy Jones Ackerman, 65, twice in the head. He then killed his stepson, Matthew Earl Black Thunder, 41, and the stepson’s girlfriend, Winona “Nona Sioux” Longee, 35, while they slept. The murders occurred during a drug-fueled episode, with methamphetamine identified as a contributing factor.
Arrest and Confession
Ackerman was detained at his home shortly after the killings. He provided a confession, and tribal law enforcement discovered the victims at the residence. One of Ackerman’s adopted sons reportedly called the Yellowstone County Sheriff’s Office to report the events.
Trial and Sentencing
In January, Ackerman pleaded guilty to second-degree murder and use of a firearm during a crime of violence under a plea agreement that limited the charges to two counts. Prosecutors had requested 27 years and six months, while the defense sought a lower sentence, citing Ackerman’s “almost zero criminal history” and portrayal as a “warm person” despite the crimes.
The court ultimately sentenced Ackerman to 15 years and six months in prison, with an additional five years of supervised release following his term.
Background
At the time of the murders, Ackerman worked as a plumber and had expressed interest in running for tribal government office. Defense notes described the killings as “senseless acts of violence fueled by methamphetamine” with no discernible motive.
