Federal prosecutors have filed murder charges in the deaths of two women in separate incidents on the Spirit Lake Indian Reservation.

Court documents show that 38-year-old Billy Joe Herman is charged with felony murder, kidnapping and assault with intent to commit murder in connection with the October 2015 death of 36-year-old Amanda Engst. Her body was found in February 2016 in the Sheyenne River south of Warwick.

Authorities say Engst was strangled and beaten to death.

Two men are accused in the August 2016 death of 27-year-old Carla Yellowbird. Twenty-four-year-old Dakota Charboneau and 20-year-old Daylin St. Pierre are charged with felony murder and conspiracy to commit robbery. Yellowbird's body was found in September 2016 near St. Michael.

Authorities say the suspects shot Yellowbird while robbing her of drugs and money.