The federal case ended with a guilty plea and a 186-month prison sentence.
BILLINGS, Mont. — A call to Yellowstone County authorities set off the investigation that ended with Michael J. Ackerman sentenced to 186 months in federal prison for a triple killing at his Poplar home.
The call came in the early morning hours of Sept. 14, 2025, three days after prosecutors said the shootings happened. Deputies were told Ackerman had admitted killing three people on the Fort Peck Indian Reservation. That report sent law enforcement from Billings to Poplar and later into federal court, where Ackerman pleaded guilty in January to second-degree murder and a firearm charge.
Deputies first contacted Ackerman inside a house in Billings, according to the government’s court filings. They read him his Miranda rights, and he agreed to speak. He told deputies he had been at his Poplar home on Sept. 11 with the other people in the house and said they had been using methamphetamine. Ackerman said he believed the others were “setting him up.” He then described a sequence that began in a bedroom with Jane Doe 1, who he said had a pistol in her hand. Ackerman told deputies he picked up his Smith & Wesson 9 mm pistol and shot her twice in the head.
The statement did not stop there. Ackerman told officers he heard movement in the next room, where John Doe and Jane Doe 2 were sleeping. He said he walked into that room and shot both of them. He then told deputies they would find the bodies inside his residence in Poplar. The victims were later publicly identified as Earlene Lucy Jones Ackerman, 65, Matthew Earl Black Thunder, 41, and Winona “Nona Sioux” Longee, 35. Earlene Ackerman was Michael Ackerman’s wife, Black Thunder was his stepson, and Longee was Black Thunder’s girlfriend.
Yellowstone County contacted Fort Peck Law and Justice Department officers, who went to the Poplar residence. No one answered. Officers received a telephonic search warrant from Fort Peck Tribal Court and entered around 5:30 a.m. Inside, they found the three people Ackerman had described. All three had gunshot wounds. Court filings said four 9 mm casings were near the bodies. The discovery turned the Billings report into a federal homicide case involving tribal law enforcement, county deputies and the FBI. Authorities did not announce any search for another suspect after the bodies were found.
Federal prosecutors first charged Ackerman, also known as Michael J. Littlebull, through a complaint alleging three counts of second-degree murder. He appeared in federal court in Great Falls on Sept. 17, 2025, before U.S. Magistrate Judge Timothy J. Cavan. At that stage, prosecutors said second-degree murder carried a maximum penalty of life in prison, a $250,000 fine and five years of supervised release. Cavan ordered Ackerman detained while the case moved forward. The complaint was an accusation at that time, and Ackerman remained presumed innocent until his later guilty plea.
The plea came Jan. 29 before Chief U.S. District Judge Brian M. Morris. Ackerman admitted to one count of second-degree murder and one count of using a firearm during a crime of violence. The plea removed the need for a trial on the original triple-murder complaint and narrowed the formal conviction to two counts. It did not settle the length of the sentence. Morris was left to weigh the U.S. Sentencing Guidelines, the statutory factors, the facts in the filings and the arguments from both sides before deciding how much time Ackerman would serve.
Prosecutors asked for 27 years and six months in prison. Their argument centered on the number of victims, the violence described in Ackerman’s own statements and the use of a firearm inside a home. The defense asked for a lower sentence and called the case “a conundrum.” Defense filings cited Ackerman’s “almost zero criminal history,” his methamphetamine use and his age. The defense also said there appeared to be no motive. In the defense account, the victims were close family or household ties: a wife of 35 years, a stepson Ackerman helped raise and that stepson’s girlfriend.
Morris imposed 15 years and six months in prison, a term far below the government’s request but still longer than the defense sought. He also ordered five years of supervised release. The sentence turned the case from an active prosecution into a completed federal judgment, though the length of the term remains striking because the underlying facts involved three deaths. Ackerman was 74 when sentenced. If he serves the full term, he would be in his late 80s before the supervised release period begins. Federal prison credits and rules can affect actual custody time, but the judgment set the sentence at 186 months.
The investigation’s route shows how the case crossed local and federal lines. The first report came to Yellowstone County deputies in Billings. The bodies were found in Poplar on the Fort Peck Indian Reservation. Fort Peck officers got the warrant and entered the residence. The FBI joined the investigation, and the U.S. Attorney’s Office prosecuted. Assistant U.S. Attorney Kalah Paisley handled the case. Those steps placed the killings in federal court rather than a state courthouse and brought the case before judges in Great Falls and the District of Montana.
By sentencing, the core public record was built around Ackerman’s reported confession, the warrant-backed entry into the Poplar home and the recovery of the bodies and casings. The court filings did not give a detailed account from any surviving witness inside the house at the time of the shootings. They also left unanswered what, if anything, happened between Sept. 11 and Sept. 14 before the call to deputies. The government’s filings said Ackerman admitted the shootings, described the location of the bodies and linked the violence to methamphetamine use and his belief that the victims were setting him up.
The case now stands as a federal conviction and sentence. Ackerman is to serve 186 months in prison, followed by five years of supervised release if he is released.
Author note: Last updated June 29, 2026.