At 1930 Central time, the airplane collided with the ground while maneuvering on final approach. Visual conditions prevailed. The private pilot and one passenger were killed. The pilot contacted the tower at 1924, reporting he was 12 miles out for landing. At 1927, the pilot reported the airport in sight and stated he would have to make a 360-degree turn to lose altitude. At 1929, the pilot reported a three-mile final. The controller observed the airplane left of the runway and then to the right of the runway. He observed the left wing drop down and the airplane impacted the ground. A witness at the airport reported it appeared the pilot was approaching a different runway than cleared by ATC. The witness heard the engine increase in power and observed the airplane as if it was trying to turn back to the other runway. It then entered a nose-dive into the ground.