The airplane impacted mountainous terrain at about 1834 Pacific time. The Private pilot/owner, the sole occupant, was fatally injured and the airplane was destroyed. Night visual conditions prevailed. At 1833, the pilot reported that he had the airport in sight and wanted to cancel VFR services. The controller terminated radar services, the pilot was instructed to squawk a 1200 beacon code, and the pilots frequency change was approved. No further radio transmissions were received from the pilot. Over the last minute of flight, radar data indicated that the radar target was descending from 4200 feet, through 4000 feet. The last recorded radar return at 1834 showed an altitude of 3500 feet about four miles northeast of the accident site. The airplane was located the following afternoon by local county sheriffs air unit. The air units crew flying the night of the accident reported a patchy and broken cloud layer with mountain obscuration in the general area. They also stated that it was a very dark night.