Poplar man sentenced for killing wife, stepson and stepson’s girlfriend

A Poplar man was sentenced to 15 and six months in prison for killing his wife, his stepson and his stepson’s girlfriend in the heat of a meth bender.

Michael Joseph Ackerman previously admitted in U.S. District Court to second-degree murder and use of a weapon in second-degree murder. Ackerman fatally shot Earlene Lucy Jones Ackerman, 65, Matthew Earl Black Thunder, 41 and Winona “Nona Sioux” Longee, 35, before driving to Billings, where he surrendered to authorities.

“This case presents a conundrum,” wrote Assistant Federal Defender Clark Matthews, who represented Ackerman in the case, in court documents filed leading up his client’s sentencing.

“Michael J. Ackerman, at 73 years of age (now 74), with almost zero criminal history, killed three people while under 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 documents continued. "There appears to be no motive, instead this was a senseless act of violence fueled by methamphetamine and made easier by the use of a firearm.”

Early on the morning of Sept. 14, 2025, the Gazette previously reported, members of the Yellowstone County Sheriff’s Office received a call from one of Ackerman’s adopted sons, who was living in Billings. He told law enforcement that his dad had driven from Poplar after killing three people.

YCSO deputies detained Ackerman, who admitted to shooting his wife, Black Thunder and Longee dead at his Poplar home. Ackerman said they were all doing methamphetamine together, and he became paranoid, thinking the three were “setting him up.” He grabbed a handgun, killed his wife, then killed his stepson and girlfriend as the two slept. YCSO relayed Ackerman’s confession to Fort Peck law enforcement, who found the three victims in Ackerman’s home.

Federal prosecutors filed criminal charges against Ackerman less than a week after the homicides. In January of this year, Ackerman reached a plea agreement with the federal government in which he admitted to a single count of second-degree murder.

In court documents filed earlier this month, Ackerman’s attorney said the septuagenarian had a limited criminal history and had never been violent toward his wife or any other members of his family, describing the triple homicide as “an isolated instance of psychosis brought on by Michael’s decision to use methamphetamine.” Ackerman, U.S. Army veteran, was a retired plumber who had ambitions of running for tribal government at the time of the killings.

“To make this case all the more perplexing,” Matthews wrote in his sentencing recommendation, “Michael J. presents as a very warm person. Throughout this entire legal process, Michael J. has been polite and respectful.”

Matthews asked U.S. District Judge Brian M. Morris, who presided over the case, for a 12-year prison sentence. Federal prosecutors recommended a 330-months sentence, putting Ackerman in prison for over 25 years.

“The sentence recommended by the United States may seem draconian given Ackerman’s advance age. But the reality is that Ackerman, paranoid and under the influence of methamphetamine, violently murdered three human beings, people he was supposed to love and protect, two of whom were sleeping and defenseless when he shot them,” wrote Assistant U.S. Attorney Kelsey Sabol in her sentencing memorandum.

“The people Ackerman murdered were deeply loved and their lives had intrinsic value beyond their relationships to Ackerman. He must be justly punished for the damage and pain he has inflicted.”

The FBI, Fort Peck Tribes Department of Law and Justice and Yellowstone County Sheriff’s Office all contributed to the investigation the resulted in criminal charges against Ackerman. Along with the 186-month prison sentence, Morris ordered that Ackerman be under federal supervision when he is released from custody. By then, he’ll be nearly 90 years old.