OLYMPIA, Wash. -- A concert at The Evergreen State College ended in a disturbance in which a Thurston County sheriff's patrol car was overturned and looted.

Washington State Patrol Trooper Brandy Kessler said officers were pelted by rocks early Friday but there were no serious injuries.

She says it began about 1:30 a.m. when a fight broke out at the 'Dead Prez' concert and a campus police officer tried to arrest a concertgoer for misdemeanor assault.

Kessler said a crowd of about 200 surrounded the officer's car, demanding that the man be let go, so the officer called for backup.

"Some people blocked the police car that was trying to take the student away," said Dan Hilden, a 20-year-old Evergreen student who attended the concert.

Sheriff's deputies responded and removed the campus officer and her car and released the man, since they knew his identity and he could be summoned later to court.

A deputy's car was disabled and when it wouldn't start, the crowd overturned it, broke out the windows and wrote graffiti on it. Kessler said the deputy's laptop computer and a radar gun were stolen. No weapons were lost.

Troopers and a Thurston County SWAT team dispersed the crowd using pepper spray with no more arrests.

Alvina Wong, who was at the concert, says both sides were wrong and the crowd may have interpreted the rap duo's comments as encouragement to rebel.

"They did suggest that the crowd should question why this guy was being detained," she said. "It's not their message to destroy police cars or anything. It's just, they want people to be more aware... and to have that awareness in the decisions that they make."

Samples of saliva and blood from people who cut themselves on the overturned car were being tested for DNA evidence that may help identify those responsible, Kessler said.

Thurston County Chief Criminal Deputy James Chamberlain said officers made the right call in releasing the man because of the unruly crowd.