The National Park Service is investigating the theft of artifacts from an archeological site in Lewis and Clark National Historical Park. 

A portion of the Astoria park was severely damaged last month by unauthorized digging. 

“Somewhere around March 20, we had someone who did an amazing amount of damage to an archeological site in the park,” said Jon Burpee, the park’s superintendent. “We’re looking for any information that folks might have that might help us solve this mystery a little bit.”

Burpee didn’t disclose specifically what kind of artifacts were taken, citing the ongoing investigation. 

“[The artifacts] don’t reach as far back as our Lewis and Clark period at the park, but they’re still very significant and part of the overall story of that landscape and how it was used over time,” he said. 

A news release from the National Park Service Investigative Services Branch states there was approximately “15 cubic yards” of soil disturbed — “the size of one and a half dump trucks.”

The release also states that evidence at the scene shows that a metal detector was used to locate artifacts. 

The damaged area is home to a rare salt marsh plant association. The plant community is “so uncommon it is classified as imperiled in the state of Oregon,” said Carla Cole, a park national resource program manager, in the news release.

The National Parks Service is asking members of the public with any knowledge of the incident to reach out.