GREAT FALLS — Jason Avery Mattson of Browning, who admitted murdering a man and then holding a woman hostage at knife-point, was sentenced in federal court in Great Falls on Wednesday.
Mattson, 30 years old, pleaded guilty on March 30 to second degree murder and to kidnapping as charged in an indictment.
Prosecutors said that on March 3, 2020, law enforcement officers were called to a clearing near Cut Bank Creek, near the Boarding School community on the Blackfeet Indian Reservation, after a body was found.
The body was identified as "John Doe" and family was notified of his death. An autopsy confirmed the manner of death as homicide and determined that Doe sustained blunt force injury to his back and extremities and that there was evidence on the neck consistent with strangulation or blunt force injury.
On March 10th, Mattson called Blackfeet Law Enforcement Services (BLES) Dispatch. In recorded calls, he told the dispatcher that he wanted to make a confession - that he had killed Doe. When asked for clarification, he provided Doe’s full name, and said that he had killed him. When asked his name, the caller identified himself as Jason Mattson. He told dispatch that he had a knife and a gun. While officers were responding to the residence, Mattson called again and told dispatch that he had taken a hostage.
He was holed up in the bedroom of a family member’s home and was holding a hostage at knife-point. When asked who he was holding hostage, he identified Jane Doe by name. When asked why he was holding her hostage, Mattson said it was because he killed John Doe. When asked what was going through his mind, he said that he was going to kill Jane Doe. At one point, Mattson said that he liked to kill. The dispatcher could hear the hostage crying and begging to be let go.
Mattson held Jane Doe hostage by knifepoint for approximately four hours before she was able to escape. Shortly after she escaped, Mattson was taken into custody.
Chief U.S. District Judge Brian Morris presided, and sentenced Mattson to 26 years and eight months in prison, followed by five years of supervised release, Acting U.S. Attorney Leif Johnson said in a news release.
Assistant U.S. Attorney Kalah Paisley prosecuted the case, which was investigated by the FBI, Bureau of Indian Affairs and Blackfeet Law Enforcement Services.