U.S. Government UFO Files:
“FBI Records: The Vault: Unexplained Phenomenon”
(Federal Bureau of Investigation, Washington, D.C.)

“The Vault”, the new FBI website, contains the following UFO files: Guy Hottel, Majestic 12, National Investigations Committee on Aerial Phenomena (NICAP), Roswell UFO, Animal Mutilation, UFO and Project Blue Book (UFO):

http://vault.fbi.gov/unexplained-phenomenon

(wikimedia.org image)