Unidentified: Inside America's UFO Investigation is a History Channel TV series purportedly exposing the US government's secret programs investigating unidentified flying objects (UFOs). It features former military counter-intelligence officer and alleged whistleblower Luis Elizondo, who claims to have directed the Defense Intelligence Agency's Advanced Aerospace Threat Identification Program. Elizondo supposedly resigned after he became frustrated that the government was not taking the UFO phenomenon, which he considered to be a national security threat, seriously enough.