Huge update after destruction of protected and delicate natural rock formations in beloved national park

Federal authorities have provided a huge update in their investigation into two men who were caught on camera destroying a protected and delicate natural rock formation.

Wyatt Clifford Fain, 37, and Payden David Guy Cosper, 31, have been indicted by a grand jury for allegedly pushing 'large chunks of ancient rock formations over the edge of a cliff onto the ground below' at Lake Mead National Recreation Area in April, the US Department of Justice announced Friday.

The incident reportedly occurred while the two men were hiking on or near the Redstone Dunes Trail, and a video taken by a witness to the event allegedly shows the two men working hard to shove the rock formation - estimated to be 140 million years old - off the edge.

A young girl, the daughter of one of the men, could be seen standing behind them, horrified, and screaming intermittently as the rocks fall.

'Daddy, don't fall,' she yelps as the two men push boulder parts over the edge and watch them break as they smash down the side of the cliff. 

Officials at the time called the behavior extremely damaging, noting that the ancient stones cannot be fixed.

John Haynes, a public information officer for the park, told KVVU: 'It’s one of my favorite places in the park and they’re up there just destroying it. I don’t understand that.'

'Why would you even do something like this? Like, why on Earth would you do this? This almost feels like a personal attack in a way,' he added.

Federal prosecutors now say Fain and Cosper's actions resulted in damages in excess of $1,000.

As a result, the two men are each facing one count of injury and depredation of government property and one count of aiding and abetting.

They were arrested by the US Marshals Service, and the pair made an initial court appearance on Friday, in which they both pleaded not guilty, according to the Las Vegas Review-Journal.

They were then released on their own recognizance - meaning that only an oath is required in order to be released.

But court records  obtained by DailyMail.com show Fain has previously been arrested for charges including assault with the use of a deadly weapon, reckless driving, destruction of personal property and domestic battery by strangulation.

If convicted on the new charges for allegedly destroying the ancient rock formation, both Fain and Cosper could face up to 10 years in prison.

Their jury trial has been scheduled for October 8. 

In the meantime, officials ask Lake Mead parkgoers to be vigilant.

The Lake Mead National Recreation Area, which is just outside of Las Vegas, sees about 6 million visitors each year.

Park staff cannot be physically present across the entirety of the 2,344 square mile area, which means they sometimes rely on the public to keep watch over some of the sites in the park.

'It is 1.5 million acres. We have two big lakes, a chunk of the Colorado River. It gets pretty difficult based on our staff levels to be everywhere all at once,' said Haynes. 

To help the park staff keep an eye on the public, the National Park Service operates a tipline that receives thousands of submissions every year.