Fort Belknap law enforcement officers and the FBI are investigating after a woman was found dead on the icy Milk River near the Fort Belknap Agency Dam.

Fort Belknap officials say the body was found at about 4:30 p.m. Monday.

An autopsy was to be performed in Billings on Wednesday. Blaine County Undersheriff Chris Adair said the woman was 33-year-old Thomasine Walker of Fort Belknap.

Adair said he did not believe she had been reported missing.