A federal judge imposed more than 15 years in prison after a defendant admitted killing his wife, stepson and his stepson’s girlfriend in 2025.
BILLINGS, Mont. — A 74-year-old Montana man who admitted shooting and killing his wife, stepson and his stepson’s girlfriend inside a home in September 2025 was sentenced this week to 15 years and six months in federal prison, bringing a close to a case that shocked family members and drew debate over the punishment imposed.
Michael Joseph Ackerman previously pleaded guilty to second-degree murder and using a firearm during a crime of violence in connection with the deaths of Earlene Lucy Jones Ackerman, 65, Matthew Earl Black Thunder, 41, and Winona “Nona Sioux” Longee, 35. The sentence was substantially lower than the prison term sought by federal prosecutors but higher than the sentence requested by the defense. The case centered on a deadly episode that investigators said was fueled by methamphetamine use and paranoia inside a family residence.
The killings occurred on Sept. 14, 2025. According to court records summarized during sentencing, Ackerman had been using methamphetamine at the home when he became convinced that members of his family were plotting against him. Prosecutors said he armed himself with a Smith & Wesson 9 mm pistol and first shot his wife twice in the head. He then heard movement coming from another room where Black Thunder and Longee were staying. When he entered the room, investigators said, the couple was asleep. Prosecutors alleged that Ackerman shot both of them while they slept. The violence unfolded within minutes and left three family members dead before authorities were alerted. Later that day, one of Ackerman’s adopted sons contacted law enforcement and reported that the defendant was driving after the shootings. Deputies subsequently located and detained him.
Investigators said Ackerman later confessed after being taken into custody. Tribal law enforcement officers and other authorities then discovered the victims at the residence. The deaths immediately triggered a homicide investigation involving multiple agencies because the crimes occurred within federal jurisdiction. Prosecutors described the shootings as deliberate acts carried out after Ackerman’s drug use led him to believe, without evidence, that relatives were “setting him up.” Court filings indicate that investigators found no indication of a long-running dispute that would explain the attack. Instead, prosecutors and defense attorneys alike described the killings as senseless and devastating. The deaths affected several branches of the same family and left relatives struggling to understand how a man with little prior criminal history could commit such violence. While the defendant accepted responsibility through a guilty plea, many questions about his state of mind at the time of the shootings remain tied to his methamphetamine use and the paranoia investigators said accompanied it.
The sentencing proceedings highlighted competing views of how the court should weigh the circumstances. Federal prosecutors asked for a sentence of 27 years and six months, arguing that the gravity of three deaths justified a much longer prison term. Defense attorneys, however, pointed to Ackerman’s age, limited criminal history and longstanding family relationships with the victims. In a sentencing memorandum, defense counsel described the case as “a conundrum,” noting that the victims included his wife of 35 years, a stepson he had helped raise and the stepson’s girlfriend. Attorneys argued there was no identifiable motive beyond drug-induced paranoia. The plea agreement itself focused on the charges rather than a recommended punishment, leaving the final sentence to the court. That arrangement allowed both sides to present sharply different views regarding the appropriate prison term while avoiding a lengthy trial over the facts of the case.
Federal court records show that Ackerman pleaded guilty in January 2026. The plea resolved the prosecution without requiring witnesses and family members to testify publicly about the killings. By accepting responsibility, Ackerman avoided the uncertainty of trial and potential additional legal proceedings. The court ultimately imposed a sentence of 15 years and six months in federal prison. While shorter than prosecutors sought, the punishment exceeded the defense request. The sentence reflects the court’s effort to balance several factors, including the number of victims, the defendant’s age, his admission of guilt and the role that drug use appeared to play in the crimes. After serving his prison term, Ackerman may also face supervised release conditions imposed by the federal court. No further criminal proceedings are expected unless issues arise during post-sentencing review.
The case left behind a painful record of loss for relatives and community members connected to the victims. Earlene Ackerman had been married to the defendant for decades. Black Thunder was her son, and Longee was his girlfriend. Their deaths transformed what had been an ordinary September day into a tragedy that reverberated through multiple families. Court filings and statements submitted before sentencing emphasized the absence of any apparent warning signs that such an attack would occur. The violence also underscored concerns raised by law enforcement officials about methamphetamine abuse and the unpredictable behavior that can accompany severe drug-induced paranoia. Although the legal process has now largely concluded, the consequences continue for surviving relatives who lost three loved ones in a single incident. The case stands as one of the more disturbing homicide prosecutions in the region because of both the familial relationships involved and the speed with which the killings unfolded.
The matter now enters its final phase following sentencing. Ackerman remains in federal custody and will serve the prison term ordered by the court. Barring future appeals or sentence-related motions, the case is effectively resolved. The next milestone will be the completion of the federal prison intake and designation process, which determines where the defendant will serve his sentence.
Author note: Last updated June 1, 2026.