YOSEMITE NATIONAL PARK, Calif. (AP) — Yosemite National Park officials are seeking witnesses who saw vandals tag more than 30 sites in the California park with graffiti.

Park officials said in a social media post on Sunday that vandals last month used white and blue spray paint to draw graffiti on boulders and other sites along the Yosemite Falls Trail.

They say that on May 20 park rangers received multiple reports of vandalism along the trail.

Rangers found more than two dozen places where graffiti had been spray-painted.

Photos posted on social media show rocks tagged with the word “Fresno” and other illegible writings.