The pilot had called another pilot on the radio and said that he was 5 mi south of the airport and returning to land. When the pilot did not return, the other pilot took off to search for the pilot. The airplane was located 3 mi south of the airport. Examination of the airplane revealed the airplane impacted the terrain nose first at a 40-45 deg angle. The propeller appeared not to have been turning at impact. An exam of the engine found no mechanical discrepancies. Toxicological results were positive: blood screen - 1026 ng/ml diazepam, 1142 ng/ml nordiazepam; urine screen - methamphetamine, amphetamine, oxazepam, temazepam, and nordiazepam identified. The level of diazepam would indicate that the pilot was taking the tranquilizer Valium at a level of at least twice the normal therapeutic concentration. In addition, the autopsy revealed a severe occlusion of the left anterior descending artery, at its origin. The degree of occlusion was sufficient to have caused arrhythmia, infarct or even death at any time.