An autopsy was scheduled for today on the body of a man found dead Sunday in Kalalau Valley on Kaua'i, but police said they do not suspect foul play.

The identity of the man was not released yesterday. The victim is believed to be in his 50s and to have been one of several people who had permanent camps in the 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.

The woman told D'Attilio that the victim had camped in the valley for several years and was "well-liked by everyone." He said the woman was a friend of the victim and would often help him pick up provisions.

Because the valley is so remote, there is no cell phone coverage, and writing messages in the sand is one of the few methods of communication by people who camp in the valley, D'Attilio said.

"I've seen that many times," he said. "In fact, when I do flights around the island, I always look there to see if there's an SOS because that's the only way they really have to signal us that there's a problem."