The interview with Doyle Rees can be read here: Transcription
On 18 September 1947, the United States Army Air Forces (USAAF) became an independent service with the establishment of the United States Air Force. Consolidating a number of investigative functions that were previously separate in the USAAF, the Air Force Office of Special Investigations (AFOSI) was instituted on 1 August 1948, patterned after the Federal Bureau of Investigations as a field operating agency under the direction and guidance of Secretary of the Air Force/Inspector General. Assets and personnel of the Army Counter Intelligence Command serving with the Air Forces were transferred to the AFOSI. Its mission included counter-intelligence, criminal investigations, certain functions under the Air Inspectors Office, and some intelligence functions.
Colonel Doyle Rees was a lawyer experienced in cases involving the defrauding of the Air Force by contractors. He was appointed to command the newly created 17th District OSI, which included New Mexico and parts of Texas, and would soon become embroiled in the "flying disc" and "green fireball" investigations. In this endeavor he was assisted by Dr. Lincoln LaPaz, head of the Institute of Meteoritics at the University of New Mexico and recognized expert on meteors. LaPaz had witnessed both UFOs and green fireballs, while Col. Rees was skeptical of flying saucers, he was convinced that green fireballs were a reality as both he and his wife had witnessed one.
The green fireball phenomenon involved observations of bright green meteor-like phenomenon over the Southwest, observed by intelligence officers at Kirtland AFB, Air Defense Command people, and some of the most distinguished scientists at Los Alamos Scientific Laboratory. Spanning a period from 1943 to 1950, the 17th District OSI compiled over 209 reports of UFOs and green fireballs. The Air Force eventually asked for the assistance of Dr. Joseph Kaplan, a world-renowned authority on the physics of the upper atmosphere, who made a special oral presentation on the problem to the Air Force Scientific Advisory Board in 1949. In early 1950, the USAF established "Project Twinkle," a network of green fireball observation and photographic stations. Never fully implemented, it was discontinued two years later with the official conclusion that the phenomenon was probably natural in origin, a hypothesis disputed by LaPaz and others.
Col. Doyle Rees had left the 17th District by this time and had no connection with the UFOs for the remainder of his career.