Authorities say a land surveyor found a man's body in the Neosho River, upstream of Grand Lake Tuesday afternoon.
The state Medical Examiner's office identified the body as that of Andrew Olsen, 27, of Grove. The ME's office has not yet performed an autopsy to learn the cause of death.
The Grand River Dam Authority called the Oklahoma State Bureau of Investigation for assistance as the death is considered suspicious, according to the OSBI.
OSBI continues to investigate.