Just before leaving his Defense Department job two months ago, intelligence officer Luis Elizondo quietly arranged to secure the release of three of the most unusual videos in the Pentagon's secret vaults: raw footage from encounters between fighter jets and anomalous aerial vehicles" - military jargon for UFOs. In interviews, he said his ultimate intention was to shed light on a little-known program Elizondo himself ran for seven years: a low-key Defense Department operation to collect and analyze reported UFO sightings. The existence of the program, known as the Advanced Aviation Threat Identification Program, was confirmed officially for the first time Saturday by a Pentagon spokesman. Spending for the program totaled at least $22 million. The funding officially ended in 2012. But officials familiar with the initiative say the collection effort continued as recently as last month. The program operated jointly out of the Pentagon and, at least for a time, an underground complex in Las Vegas managed by Bigelow Aerospace, a defense contractor that builds modules for space stations. It generated at least one report, a 490-page volume that describes alleged UFO sightings in the United States and numerous foreign countries over multiple decades. The first public revelations of the program came in a video conference aired in October by To the Stars Academy for Arts and Sciences, the firm Elizondo joined as a consultant after retiring from his Pentagon job.