The state's top law enforcement agency is investigating after sheriff's deputies discovered a body on the Washita River earlier this week.
The Oklahoma State Bureau of Investigation took over the case after the medical examiner notified authorities about suspicious injuries found on the body.
The Custer County Sheriff's Office was initially called Wednesday after the body was discovered on the river south of the town of Clinton in western Oklahoma.
The OSBI used fingerprints to identify the man as 39-year-old Thomas Beebe. Investigators said Beebe was on probation in North Dakota and transferred to New Mexico to live with his mother.
The New Mexico probation office had reported him missing in March