(Bethel, AK) –At the end of last month, Superior Court Judge William Montgomery sentenced 40-year-old Byron Demantle, to 33 years for sexual assault in the first degree.

Demantle pled guilty to sexually assaulting three women in Kwethluk between 2020 and 2022. He pled guilty in April 2025, on the first day of trial. Demantle was charged with sexually assaulting three women and attempting to sexually assault a fourth woman. As part of his plea agreement, Demantle admitted to sexually assaulting the three women and attempting to sexually assault the fourth. Several months after he pled guilty, Demantle moved to withdraw the guilty plea that he had entered. After extensive litigation, Judge Montgomery denied Demantle’s request and sentenced him in accordance with the plea agreement Demantle made during jury selection for trial.

Judge Montgomery sentenced Demantle to serve 50 years with 17 years suspended, with 33 years to serve. He also placed Demantle on probation for 15 years following his release from custody, which will occur when Demantle is 69-years-old. Demantle will be required to register as a sex offender quarterly for the remainder of his life.

Assistant Attorney General Bailey Woolfstead of the Office of Special Prosecutions’ Rural Prosecutions Unit prosecuted the case with the assistance of Paralegal Bethany Kaiser of the Bethel District Attorney’s Office. The Alaska State Troopers investigated the case.