Witnesses to the most famous UFO encounter of modern times say they were told to wipe tapes and hard drives containing evidence of the incident.
In 2004, Navy pilots and crew aboard the USS Princeton and USS Nimitz were buzzed by strange objects that pulled off moves impossible for any known aircraft. Footage of the encounter shot by a pilot was first made public in 2017 by a UFO group set up by punk singer Tom DeLonge of Blink 182, which US authorities later admitted was real.
Now, in a twist right out of cult TV show The X-Files, navy veterans on the two ships have revealed they were told to delete the evidence.
Technician Gary Voorhis, based on the Princeton, told magazine Popular Mechanics they first noticed something was amiss when "ghost tracks" and "clutter" appeared on the radar. After fixing what they thought was a malfunction, the tracks actually became "sharper and clearer".
He was able to spot the mystery craft through a pair of binoculars.
"I couldn't make out details, but they'd just be hovering there, then all of a sudden, in an instant, they'd dart off to another direction and stop again," he told Popular Mechanics.
After a few days of seeing the objects in the distance and picking them up on radar, fighter jets were sent out to intercept them - shooting the now-infamous footage released by DeLonge.
"In the video I saw, you got a good sense of how the pilot was having a difficult time trying to keep up with this thing. It kept making tight, right-angle turns."
On the Nimitz, Petty Officer Patrick Hughes wasn't aware of the UFOs. One of his jobs was to secure hard drives containing data collected by an early-warning system designed to detect incoming aircraft. But on November 14 - the same day the pilots shot their close-up footage of the UFO - he was approached by his commanding officer, who was accompanied by two men he'd never seen before.
"They were not on the ship earlier, and I didn't see them come on. I'm not sure how they got there," he told the magazine.
He was told to hand over the drives.
On the Princeton, Voorhis said two guys showed up "on a helicopter" to take away some of the data he'd recorded, and to "erase everything" left behind - "even the blank tapes".
Another unnamed witness told the magazine the mysterious officials arrived in a Blackhawk helicopter "and took all our information from the top secret rooms. We were all pretty shocked and it was an unspoken rule not to talk about it because we had secret clearances and didn't want to jeopardise our careers."