MYSTERY WIRE — It was 13 years ago when only a select few people knew that the U.S. congress authorized a secret study of UFOs and nuclear weapon facilities.

In 2007, then Senate majority leader Harry Reid and two of his most trusted Senate colleagues conferred in a highly secure room about the perplexing mystery of UFOs. The three senators agreed to authorize black budget funds for a study by the Defense Intelligence Agency (DIA) into UFO incidents and related phenomena.

Sen. Reid said one reason he wanted a formal study was a series of dramatic incidents where UFOs appeared over American nuclear weapons facilities. These are cases that have been documented in a book and film by investigator Robert Hastings. You can watch Hasting’s film on his website and on Amazon Prime Video.

A group of more than 150 military veterans, missile officers, and security personnel, including many who worked at the Nevada Test Site, say they’ve seen mystery intruders over nuclear facilities.

“Over the last 43 years, I’ve interviewed over 150 U.S. military veterans,” Hastings said during a 2016 interview, “persons who were nuclear launch officers, nuclear missile targeting officers, maintenance personnel, security guards who guarded the nuclear weapons facilities, and all of those individuals have told me on tape either audio or video that in fact UFOs have routinely monitored our nuclear weapons dating back decades. And that on occasion appear to have interfered with the functionality of those weapons.”

Hastings brought some of his key witnesses forward in 2010 during an event at the national press club. Since then, he’s been contacted by even more first hand witnesses, all of them ex-military.

In 1955, 14 A-bombs were detonated as part of Operation Teapot at the Nevada test site, witnessed by thousands of military personnel in trenches, and by thousands of test site employees. But there were other observers as well. “It was what we called flying saucers. They were pretty prevalent at the test site back then,” said a former test site photographer.

At least a dozen former test site employees have told similar stories about unknown aircraft showing up hours or days after an atomic blast.

In addition to the eyewitness accounts, thousands of pages of formerly-classified documents have been released to buttress these stories. A Freedom of Information Act request filed in 1992 produced a thick stack of documents from the Department of Energy (DOE), indicating UFO incidents over every major atomic weapons facility dating to the late 1940s, over Los Alamos national lab, where the bombs were designed, over Hanford, where the plutonium was processed. But DOE has no records of any official sightings over what later became the Nevada Test Site. Hastings however, has found plenty.

Watch: UFOs and Nukes: The Secret Link Revealed

The government ended atomic weapons tests years ago, but Nevada incidents continue. Former security officers at Area 2 at Nellis Air Force Base, for years a storage facility for up to 200 nuclear warheads, have reported multiple intrusions by unknown aircraft from the late 1990s through 2004.

Recent UFO sightings at Nellis AFB

When Hastings is asked who is behind these incidents and why, he gives this answer, “Who knows what their motivation is?”

Similar incidents have been reported in the UK, India, Pakistan and other nuclear powers.