On April 13, 1997, at 1154 hours mountain standard time, a Devendorf Glassair GL25, N28BD, was destroyed when it impacted the ground in the vicinity of Congress, Arizona. The private pilot and one passenger sustained fatal injures. The flight originated at the Eagle Roost Airport, Aguilla, Arizona, on the day of the accident about 1140 hours. Visual meteorological conditions prevailed and no flight plan was filed for the local area personal flight. Two witnesses, one of whom is a pilot, both stated that they observed the aircraft when it was approximately 1,000 feet agl until impact, and that it appeared to be in an inverted spin during that time. An airworthiness inspector from the Scottsdale, Arizona, Flight Standards District Office, went to the accident site and examined the wreckage and engine. In his report, the inspector said that the aircraft appeared to have contacted the ground in an inverted attitude with little or no forward velocity. The inspector noted that no airworthiness discrepancies were noted with either the engine or airframe during the examination. The pilot's medical certificate had expired almost 2 years prior to the date of the accident. The pilot's logbook was not located to ascertain his total flight hours and time in the aircraft, or to determine if he had any prior instruction in spin recovery techniques. The forensic toxicology report from the FAA Civil Aeronautical Medical Institute stated that no controlled substances or other debilitating drugs were found. It was not possible to test for carbon monoxide or cyanide due to lack of suitable specimens.