Denver, ColoradoAugust 1958

On the evening of August 31, 1958, a civilian businessman in Denver, Colorado saw three reddish-orange objects about the size of a baseball moving in an almost straight line across the sky. The objects traveled slowly and dropped behind nearby trees, and the entire sighting lasted about 35 minutes. The observer was clear about what he had seen and was described in the file as reliable and sounding like a trustworthy person.

A second witness, also a civilian businessman about 2 miles northwest of downtown Denver, reported seeing a child observe similar objects. The child saw them slowly drop behind trees in the same general area. This second sighting lasted 35 minutes as well, and the witness was also described as reliable.

The investigation was limited by meager information. One Air Force officer noted that the report lacked sufficient detail for an accurate evaluation. However, he mentioned the possibility that equipment used to track aircraft (called IFF equipment) might not have been working properly, since a target appeared only on the IFF system and at an extremely high speed. The file contained one possible explanation: an Assistant Base Training Officer suggested the objects might have been aerial searchlights in connection with a circus.

The Air Force concluded that the objects were probably related to a balloon or were possibly connected to aircraft. However, due to the lack of detailed information, the case was listed as having insufficient data for a definitive answer. The file is reproduced below as held by the National Archives across 21 pages.