Existence of UFO's 'proved beyond reasonable doubt' as expert says earth 'could have been visited' The existence of UFOs has "proved beyond reasonable doubt", a former Pentagon official has said. Luis Elizondo, the former head of a secret US government programme, believes that Earth may well have been visited by alien life via the unidentified aircraft and that there is also proof. He resigned from the US Department of Defence in October to protest against the excessive secrecy and opposition to the programme he was in charge of. Speaking to the Sunday Telegraph , he said: "In my opinion, if this was a court of law, we have reached the point of 'beyond reasonable doubt'. I hate to use the term UFO but that's what were looking at. "I think it's pretty clear this is not us, and it's not anyone else, so one has to ask the question where they're from." Mr Elizondo could not comment whether or not his team had examined UFO sightings as it was still classified information. But he told the newspaper there had been "lots" of sightings. He ran the Advanced Threat Identification Program, funded with £16.5million, from his office in the Pentagon. The team identified movements and trends that were not like anything else "in the world". They also discovered "hotspots" during their investigation, which were often near nuclear facilities and power plants. Describing the findings, Mr Elizondo said: "Extreme manoeuvrability, hyper-sonic velocity without a sonic boom, speeds of 7-8,000mph, no flight surfaces on the objects. "A lot of this is backed with radar signal data, gun camera footage from aircraft, multiple witnesses." The Pentagon said funding for AATIP ended in 2012, but Mr Elizondo said his team's UFO work carried on for another five years. Last week he told CNN: "My personal belief is that there is very compelling evidence that we may not be alone."