SANTA CRUZ - A large group of protesters demonstrating at a May Day rally for worker's and immigrant rights downtown broke off into a riot vandalizing about a dozen businesses around 10:30 p.m. Saturday, police said.
Many in the group were carrying makeshift torches as they marched, breaking storefront windows and writing "anarchist graffiti" on buildings, according to Capt. Steve Clark.
...
The violence was initiated from a group holding a rally at the town clock for May Day. Windows at Jamba Juice and Velvet Underground were left shattered and graffiti including anarchy signs were tagged onto buildings.
Because of the size and violent demeanor of the crowd, Santa Cruz police asked for help from all agencies in the county to break up the riot. At one point, protesters lit a fire on the porch of Caffe Pergolesi and blocked access to firefighters, officers said.

because a Tea Part protest was organized nearby and they feared violence.

http://biggovernment.com/jhoft/2010/04/ ... -patriots/

The participants were vocal but well-behaved as they stood on the north side of York Street across from the OLC.

...There were a few tense moments when the crowd moved west down York toward Third Street after the president's motorcade arrived. A Secret Service agent asked the crowd to move back across the street to the north side.

When the crowd didn't move and began singing "God Bless, America" and the national anthem, Quincy Deputy Police Chief Ron Dreyer called for members of the Mobile Field Force to walk up the street.

There was no physical contact, and the officers did not come close to the crowd....[Tea Party Organizer] McQueen also assisted in asking people to step back to the north side of York. The crowd moved back, the officers stayed for about 15 minutes and left, and there were no other incidents.

"It's just a communication issue. We were trying to get them to move across the street," Quincy Deputy Police Chief Curt Kelty said. "We were just trying to move them back, they complied, and it was fine."