On December 26, 1999, about 1242 hours mountain standard time, a Beech 65-80, N184R, owned and operated by the pilot, experienced the collapse of its left main landing gear during landing rollout at Falcon Field, Mesa, Arizona. Visual meteorological conditions prevailed during the personal flight, and no flight plan was filed. The flight was performed under the provisions of 14 CFR Part 91. The airplane was substantially damaged, and neither the pilot nor the two passengers was injured. The flight originated from Mesa about 1220. In pertinent part, the pilot reported to the National Transportation Safety Board investigator that this was the first flight following the airplane's annual inspection. One uneventful takeoff and landing was performed. During the landing gear retraction process on the next takeoff, the pilot observed a cockpit indication that the left main landing gear did not normally retract. No "up lock" light illuminated. The pilot further reported that, in an effort at remedying the situation, the landing gear circuit breaker was pulled. Then, the hand pump was utilized to manually extend the gear. Following this effort, only two green landing gear position lights illuminated. The pilot stated he informed the control tower that he would be landing with an unsafe gear indication. After landing and rolling between 80 and 100 feet, the left main gear collapsed. As the airplane slid to a stop it veered into a taxi light and onto the dirt clearway. The Federal Aviation Administration (FAA) coordinator verbally reported to the Safety Board investigator that upon examination of the airplane the left gear's actuator shaft was observed broken in half, and the associated knuckle attachment bolts had been "pulled out" of the structure. No evidence of preexisting malfunction, corrosion, or other defect was noted in this area of the landing gear assembly. The FAA further indicated that although the observed overload-type failure appeared consistent with the airplane having been subjected to a hard landing at some time during its operation, no specific date(s) was determined for the occurrence.