Tongan police say an autopsy on the body found on a yacht stashed with cocaine shows no evidence of foul play.
The badly decomposed body was found last week on board the Jereve discovered wrecked on an uninhabited Tongan atoll.
200 kilogrammes of cocaine worth an estimated 120 million dollars was also found on board.
Tonga's Police Commissioner Grant O'Fee says the autopsy reveals the body belonged to a man possibly in his thirties but police await the results of more tests for clues to his identity and how he died.
"There was clearly rough weather and they've run aground. We haven't found any trauma to his head but potentially he could have become knocked out in a storm or something and (there was) an injury that's not easily discovered. It possibly could have come from that but it's just speculation. We really just don't know at the moment."
Commissioner O'Fee says police have so far not found any trace of any other person on the yacht.