Frenchman Olivier Raymond Philippe Jannequin, 42, was killed while snorkelling off Phi Phi about lunchtime on Saturday.
A friend who was in the water saw nothing unusual before discovering that Mr Jannequin was dead.
Deep cuts to his head and torso indicated he had been struck by a propellor, said Lieutenant Wisawa Sanehar, the investigating officier.
''Unfortunately there are no witnesses,'' Lieutenant Wisawa said. ''It is difficlut to take the case further.''
The friends were swimming and snorkelling off Ton Sai beach, near the main pier where day-trippers arrive and depart for Phuket, about 80 minutes away.
Mr Jannequin's death was most likely caused by a speedboat or a local longtail vessel. His body is at Krabi Hospital.
If your propeller hits a large object in water, much like a human body for example, you will most definitely notice it.
There is not one boat drive who would not stop and check what happened to the propeller.
In doing so it's very difficult not to notice the cause of the propeller strike but fat chance the driver would come forward.
Sure helps the tourist safety campaign.
Posted by Andrew on August 21, 2012 14:19