A Dupree man has been sentenced to 12 years in federal prison for the fatal stabbing of another man on the Cheyenne River Sioux Indian Reservation.
According to U.S. Attorney Ron Parsons, 27-year-old Gradyn Blue Arm was sentenced July 13 after pleading guilty to voluntary manslaughter. In addition to the prison term, Blue Arm was ordered to serve three years of supervised release and pay a $100 special assessment.
Prosecutors say Blue Arm returned to a residence in Dupree with knives on June 3, 2025, after being asked to leave. Following an argument, he stabbed another man in the abdomen. The victim later died from his injuries.
Blue Arm was indicted in September 2025 and entered a guilty plea in April 2026.
The case was investigated by the FBI and Cheyenne River Sioux Tribe Law Enforcement Services. Following sentencing, Blue Arm was remanded to the custody of the U.S. Marshals Service.
