The other two pilots, who had seen nothing and were alarmed at flying so high without oxygen, leveled off at 15,000 feet. Mantell was then above 22,000 feet and still climbing. In ship-to-ship conversation he said that he would go to 25,000 feet for about ten minutes, then come down. When all further attempts to call Mantell went unanswered, the other pilots discontinued the search and went on to their base; although one returned after refueling and equipping himself with a mask and oxygen, he found nothing in the area. At about 3:15 Mantell radioed that the object was “directly ahead of me and slightly above, and is now moving at about my speed or better. I am trying to close in for a better look.” He did not call again. Less than an hour later searchers found the crashed plane. Mantell was dead. His shattered watch had stopped at 3:18. During the period of search, ground observers at Godman Field had been able to watch the UFO, gradually diminishing in size, and about 3:50 it disappeared from view. Within a few minutes, however, observers farther south in Kentucky and Tennessee were reporting an unknown object in the sky. A hundred rumors sprang up immediately after the tragedy: that the UFO was a Russian missile; was a weird machine from outer space that had deliberately or accidentally knocked the plane out of the air when it got too close; that Captain Mantell’s body was riddled with bullets; that the plane had completely disintegrated before striking the ground; that the wreckage was radioactive. Investigators rushed in to find the cause of the fatal crash and brought confusion with them. Some facts could be quickly established. There were no bullet wounds. The plane had not burned on impact and was not radioactive. The left wing had come off while in the air and landed 100 feet from the main crash area. Parts of the plane were scattered on a line north to south within six tenths of a mile of the central wreckage. The emergency canopy lock was in place and apparently no attempt had been made to release it. The throttle was set at one fourth open, mixture control at “Idle cut-off,” and prop control at “Full increase r.p.m.” From this evidence investigators concluded that because of lack of oxygen Mantell had lost consciousness at about 25,000 feet, while his plane continued to climb to about 30,000 feet; leveling off, it then began a gradual turn to the left because of engine torque, and went into a spiraling dive that produced a speed and a structural stress greater than the plane could stand--the plane was “red-lined” (Air Force jargon for the limit of safety) at 525 mph. Pilots who have flown the P-51 in combat conditions have agreed with this conclusion and have suggested that, as the plane fell, Mantell may have regained consciousness, realized what was happening, pulled the throttle back and tried to pull back on the control, thus producing a stress so great that the wing was torn off and the plane then fell vertically.