According to ABC News, a family called 911 on May 1 to report something crashed in their backyard and they saw non-human creatures in it.
In the 911 call audio released, the caller says he, his father and his brother were in their large backyard working on their truck when something crashed and they felt an impact.
911 call released for report of UFO crash, aliens in Las Vegas
"We just see in the corner of our eye something fall down from the sky, and it was with lights, and when it hit down there was like a big impact, and we felt like an energy? And then we hear like a lot of footsteps near us. And then - we have, like, big- a big equipment, and we see there's a, there's like an eight-foot person beside it and another one's inside, and it has big eyes and it's looking at us," the caller tells the 911 dispatcher. "They're very large. They're like eight foot, nine foot, 10 foot."
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"And they're not human. One-hundred percent, they're not human," the caller adds.
Officers responded to the residence, but when they arrived there was no sign of any creatures.
Police said the officers conducted a preliminary investigation but were unable to find anything. The case was closed as "unfounded," officials said.
Las Vegas police officer investigates report of possible UFO sighting
The House Oversight Committee is in the "early stages" of preparing a hearing on UFOs in the wake of unconfirmed claims the U.S. allegedly found crashed alien spacecraft -- an account the Pentagon says is unsubstantiated.
The former intelligence official, David Grusch, had alleged on Monday that the U.S. government has a covert program focused on recovering debris from crashed, non-human origin spacecraft and is attempting to reverse-engineer the technology, the online tech outlet The Debrief reported.
There has been no public confirmation of Grusch's account, and a leading House Republican, intelligence chairman Mike Turner, also expressed skepticism about the idea that the U.S. government has recovered alien spacecraft.
Grusch has said he gave evidence of such a program to Congress and the Office of the Inspector General for the Intelligence Community, according to The Debrief.
ABC News contributed to this report.