HELENA, Mont. — A 74-year-old man has been sentenced to more than 15 years in federal prison after pleading guilty to the murders of his wife, stepson, and stepson’s girlfriend on the Fort Peck Indian Reservation. The tragic incident unfolded in September 2025, igniting a complex legal battle and drawing the attention of multiple law enforcement agencies.
Michael J. Ackerman received a sentence of 186 months following his admission of guilt to one count of second-degree murder and another count of using a firearm during a violent crime. U.S. District Judge Brian M. Morris handed down the sentence, which fell short of the prosecution’s request for 27 years and six months but exceeded the defense’s plea for leniency. Upon release, Ackerman will be subjected to five years of supervised release.
The fatalities involved Earlene Lucy Jones Ackerman, 65, Matthew Earl Black Thunder, 41, and Winona “Nona Sioux” Longee, 35. According to federal filings, Ackerman was under the influence of methamphetamine when he became paranoid, believing the three victims were conspiring against him. Describing the events as a “senseless act of violence,” the defense highlighted the influence of drugs on Ackerman’s actions and pointed to his otherwise clean criminal record.
The investigation began on September 14, 2025, when law enforcement received reports of Ackerman confessing to the killings. Yellowstone County deputies contacted him at a residence in Billings. After being read his rights, Ackerman recounted the specific details of the shootings, including how he shot his wife and later his stepson and the girlfriend in separate rooms.
With a search warrant obtained from the Fort Peck Tribal Court, officers discovered three bodies at Ackerman’s home, each with gunshot wounds. Multiple shell casings were recovered from the scene, corroborating Ackerman’s confession.
Initially charged with three counts of second-degree murder, Ackerman’s case transitioned through federal court, culminating in a guilty plea in January. Prosecutors emphasized the gravity of the crimes while the defense implored for a reduced sentence based on personal circumstances, including Ackerman’s age and the tragic nature of the familial relationships involved.
The investigation saw cooperation from various agencies, including the FBI and tribal law enforcement. Despite the chilling details surrounding the case, officials confirmed that no additional suspects were identified, as Ackerman’s statements and evidence from the scene pointed solely to his involvement.
While court documents detail Ackerman’s actions and the circumstances leading to the murders, several questions remain unresolved. The lack of clarity about the events inside the home prior to the violence and Ackerman’s decision to leave Poplar before law enforcement arrived adds layers of complexity to an already tragic narrative.
As Ackerman begins his lengthy prison term, he will face the reality of serving a sentence that could extend into his late 80s. The next phase of his case will occur once he completes his prison term, at which point he may be eligible for supervised release. The community is now left to grapple with the aftermath of a crime that has altered multiple lives forever.