BREA, Calif. -- A man drove his car slowly through marchers Thursday at an immigrant rights rally, with one demonstrator jumping on the hood as the car lurched forward and then stopped. Police quickly surrounded it and arrested the man.

Brea Police Chief Jack Conklin said none of the demonstrators sought first aid but the SEIU United Service Workers West union later released a statement saying six people were taken to a hospital for evaluation.

The union helped organize the protest, and President David Huerta said the four union members and two staffers were "victims of what appears to be a deliberate and hateful crime."

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Police disputed that.

"I think he was trying to get through the crowd," Lt. Adam Hawley said. "We don't have any indication he was trying to harm somebody."

Hawley told CBS Los Angeles police think the motorist may have gotten caught in the middle of the protesters.

But the driver, 56-year-old Daniel Wenzek, was arrested for investigation of assault with a deadly weapon, Hawley said. Wenzek was later released pending the investigation.

The demonstrators were marching about 30 miles southeast of Los Angeles. They were urging Republican U.S. Rep. Ed Royce to support an existing temporary immigration program for citizens of several Central American countries, said Andrew Cohen, a spokesman for Unite Here Local 11, a union representing hotel, food service and airport workers.

A video released by Cohen showed the car, with its horn honking the whole time, pushing through a line of demonstrators marching in a crosswalk. Several protesters pounded on the hood and one was pushed as the car inched ahead.

Another demonstrator jumped on the hood as the car pulled ahead perhaps 50 feet, then stopped in the middle of the intersection as police rushed in and ordered the marchers to get away from it.

"We ran over, fearing the worst," Cohen told CBS Los Angeles. "I think a lot of people have Charlottesville in our minds."

Cohen said Wenzek didn't say anything as he drove through the protesters.

A woman who answered a phone number linked to Wenzek refused to allow an Associated Press reporter to talk to him and hung up.

Records show Wenzek was convicted in 2006 of committing lewd acts against a child under 14.