Efforts to develop helicopters which possessed low observability characteristics commenced during the Cold War period. It was during this time that several different stealth helicopters would first emerge.[6][7] The Central Intelligence Agency (CIA) was one such party seeking such rotorcraft, during the early 1970s, a single modified Hughes 500P was produced for the agency; it had a reduced noise operation capability, leading to its nickname of "The Quiet One". It was reportedly used in at least one operation by the CIA, to deploy a wiretap during the Vietnam War.[8]