Authorities are investigating a sexual assault at Horsethief Canyon Park in San Dimas.

The assault, which was only recently reported, occurred in mid-January on the trails north of the San Dimas Dog Park, according to the Los Angeles County Sheriff’s Department.

The suspect is described only as a male adult who was wearing green cargo pants, a black sweater, and dirty, black Converse tennis shoes.

No further information was released.

“The purpose of this notification is to advise those frequenting the area of the San Dimas Dog Park to use caution and be cognizant of your surroundings,” the Sheriff’s Department said. “San Dimas Station Deputies are monitoring and providing additional safety checks of the area in addition to walking the trails to provide additional security for our community members.

Anyone with information about the attack is asked to contact the Special Victims Bureau at (562) 946-7960, or if you would like to remain anonymous, contact Crime Stoppers at (800) 222-TIPS (8477).