An autopsy was performed today on a man whose body was spotted Sunday by a helicopter tour company that saw an SOS written on Kalalau Beach. The cause of death is still pending a toxicology report and there has been no positive ID yet, said Mary Daubert, Kauai county spokeswoman.

The victim is believed to be in his 50s and to have been one of several people who had permanent camps in Kalalau Valley.

Kaua'i police and firefighters were called about 2:30 p.m. Sunday after someone spotted "SOS" written in the sand near the mouth of the valley. Officials notified Ken D'Attilio, owner of Inter-Island Helicopters, which the county has hired to provide helicopter service for search-and-rescue missions.

D'Attilio said he picked up a fire-rescue team and flew to the beach area.

There, they met a woman who led the rescue specialists to the man's camp, which was about 15 minutes into the valley, he said.

The woman told police that the man had suffered from a heart ailment, he said.

"He had died a couple of days earlier, apparently in his sleep, because he was still in his sleeping bag," D'Attilio said.

The firefighters brought the man's body to the helicopter and he was taken to the Princeville Airport and turned over to police.