Fred Ramisky, 62, and Melvin Daniel, 39, both of Puyallup, were on a hunting trip last week and staying at the Chambers Lake Campground.

The two had gone to bed Thursday night in the cabin of the trailer. A third man who was with them went to sleep in a room at the back of the trailer and later woke up with a headache and had difficulty moving, sheriff officials said.

The man found his two friends dead at the front of the trailer. The group had been using the trailer's heater to keep warm during the night.

An autopsy was scheduled Monday, but test results to confirm the presence of carbon monoxide could take several weeks.