BERKELEY (KCBS) – University of California, Berkeley police are searching for a man who they said sexually assaulted a Cal student earlier this week.

UC Berkeley police Lt. Eric Tejada said the assault took place Monday evening at around 6:30 p.m.

“A young woman was entering Griffith Hall and she was followed into the building by a subject who followed her into a stairwell and then did a sex grab on her,” he said.

Tejada said the victim did not know the suspect, and it is still not clear if the suspect is a student as well.

Police describe him as an African American male in his 20s, 6 feet tall with a thin build and medium-length dreadlocks. Tejada said he walked into the dorm behind the victim without an access card – a move called “tailgating.”

“I understand it can be tough sometimes, everybody is polite and everybody wants to help each other out,” Tejada said. “But if it does happen, change your course, call the police department immediately and go to someplace where there’s other people around.”

Jun Kim, whose girlfriend lives in Griffith Hall, said tailgating is not difficult.

“I actually know how easy it is to follow people in, especially if someone doesn’t look too sketchy,” he said.

While she was grabbed under her skirt, police said the victim was not physically injured. She screamed during the encounter and ran away.