The man who administrated a secret Pentagon program designed to investigate "extra-terrestrial craft" says that he believes the existence of UFOs has been "proved beyond a reasonable doubt."

Speaking to The Telegraph, Luis Elizondo, a career intelligence officer with the Department of Justice who served five years as the head of the DOJ's Advanced Aerospace Threat Identification Program (the so-called "X-Files"), said that in the course of his job he regularly saw aircraft that "did not belong to any nation," and that he believes Earth has most certainly been visited by alien life.

"In my opinion, if this was a court of law, we have reached the point of ‘beyond reasonable doubt,’” Elizondo told the British magazine.

“I hate to use the term UFO but that’s what we’re looking at,” he added, noting that the term "UFO" refers to any "unidentified flying object" of which "alien spacecraft" is only one of many possibilities. “I think it’s pretty clear this is not us, and it’s not anyone else, so no one has to ask questions where they’re from.”

He does claim that, for the most part, the "alien" spacecraft he studied were friendly. ​“There was never any display of hostility, but the way they maneuvered, in ways no one else in the world had, you have to be conscious something could happen," Elizondo said.

The AATIP, the brainchild of Sen. Harry Reid, shuttered in 2012, but not before interviewing "hundreds" of people, mostly members of the military, who interacted with unidentified aircraft.. After his official tenure, Elizondo says he continued to work on the issue for five more years, finally giving up in 2017 after learning that it was unlikely the AATIP would ever be re-funded.

The most detailed reports, Elizondo claims, remain classified. The Pentagon has released only about 50% of what the AATIP accumulated during its existence.