Three people were killed in Poplar, Montana, on or about September 11, 2025, and found by tribal police after a report on September 14. Victims were 41-year-old Matthew Black Thunder (born July 2, 1984), 65-year-old Earlene Jones, and 35-year-old Winona Longee, each fatally shot at close range with a small-caliber firearm; Matthew was found in a local residence with a gunshot wound.

A single suspect, 73-year-old Michael J. Ackerman, also known as Michael J. Littlebull, was taken into custody shortly after the bodies were discovered. A federal complaint says Ackerman told investigators he had been using methamphetamine with the three on September 11, believed they were setting him up, and shot them with a 9mm pistol in his Poplar residence. He was charged in U.S. District Court in Great Falls with three counts of second-degree murder and detained pending further proceedings. The FBI, the Fort Peck Tribes Department of Law and Justice, and the Yellowstone County Sheriff’s Office are involved in the investigation.

Matthew was described by family as a devoted son, brother, and uncle who enjoyed cruising, music, and pool leagues; he worked in the garden at Fort Peck Community College. Anyone who knew Matthew, Earlene, or Winona, or who has information about the killings or events around September 11–14 in Poplar, is asked to come forward.