The pair, Wyatt Clifford Fain and Payden David Guy Cosper, were captured on camera last April shoving the iconic red rock sandstone formations at Nevada’s Lake Mead National Park, home to 140 million-year-old sand dunes. Video of their act went viral and drew quick condemnation.

A jury found each guilty of one count of injury and depredation of government property after a two-day trial, according to the U.S. Attorney’s Office. They face a maximum penalty of one year in prison, a $100,000 fine, or both.

They are both set to be sentenced on July 8.