BENTON, Ill. (AP) — Authorities are still trying to confirm the identity of a man whose body was found in August at an old coal mine in southern Illinois.

The body of what officials say was a middle-aged white man was found Aug. 11 in an advance state of decay at the Old Ben No. 9 Mine site near West Frankfort in Franklin County.

Sheriff Don Jones tells The Southern Illinoisan that investigators must rely on dental records and DNA analysis for make a positive identification. Jones says investigators suspect they know the man’s identity and that man’s family has provided DNA samples for testing.

The mine has been closed since the 1960s.

Jones says the cause of the man’s death hasn’t been determined as investigators are waiting on a forensic anthropologist’s report.