The pilot reported that shortly after he exited the runway after landing, the nose landing gear collapsed. According to his written statement, “neither the flaps had been retracted yet or a command given to retract the landing gear.” He immediately shut off the mixture to the engine, took photos of the cockpit controls, and exited the airplane. Examination of the accident site and wreckage by a Federal Aviation Administration (FAA) inspector revealed that the flaps were in the down position, the nose landing gear was fully retracted, the left main landing gear was about 80% retracted, and the right main landing gear was about 50% retracted. A visual examination of the taxiway revealed a 25 ft ground scar. The airplane sustained substantial damage to the left wing. Postaccident examination of the landing gear system revealed no evidence of any preaccident mechanical malfunctions or failures that would have precluded normal operation.