Searchers combed rugged terrain for the remains of three people believed to have been aboard a single-engine private plane that crashed in inclement weather near Lake Tahoe on a flight from Seattle to Oxnard. "The wreckage was scattered over a large area in small pieces, so we don't have a positive identification of the plane and no bodies have been found," said a spokesman for the Federal Aviation Administration. He said the FAA center in Oakland lost radio and radar contact with the plane, believed to be a Beech Bonanza, as it was flying in snow showers at 17,000 feet on Saturday afternoon nine miles south of Lake Tahoe. Visibility was 200 feet. The pilot was using an instrument flight plan.