The Upper Skagit Indian Tribe is offering up to a $5,000 reward to help catch whoever looted an archeological site in North Cascades National Park.

National Park Service police have been investigating the illegal excavation of an ancient mountain-goat hunting camp. They discovered someone had dug up the “Rock Shelter” site outside the town of Newhalem, Washington, last summer.

The dig caused “irretrievable damage,” according to the park service.

The site, used for at least 1,500 years, was rediscovered in the 1980s.

Today, there’s a trail to the site and a wooden observation platform with interpretive signage to give visitors a glimpse of indigenous life in the Cascades centuries ago.

Archeologists have identified more than 160 pre-contact archeological sites in the upper Skagit valley, going back at least 10,000 years.