The president of the city Police Commission quit in a dispute over control of the police department following the videotaped beating of a motorist, and a rookie officer charged in the case was fired.

Blaming a "nasty, internal, raw fight about power" at City Hall, Dan Garcia quit on Tuesday as president of the Police Commission."Until the rules and responsibilities that govern the Police Commission are clarified, it's going to be difficult for anybody to do this job," he said.

The commission, a mayor-appointed panel that oversees the police department, has been locked in a struggle with the City Council for control of the department.

A month after the beating, the commission put Police Chief Daryl F. Gates on 60 days' paid leave, but the City Council voted to override the suspension. A judge has temporarily reinstated Gates.

Meanwhile, Gates on Tuesday fired one of the four officers charged with assault and brutality in the beating March 3 of black motorist Rodney King. The chief ordered the other officers to stand trial before a departmental board.

In firing Officer Timothy Wind, Gates said the probationary officer had used excessive force.

Also Tuesday, Superior Court Judge Bernard Kamins denied all four officers' request for dismissal of the criminal charges. Besides Wind, those charged are Sgt. Stacey Koon and officers Laurence Powell and Theodore Briseno.

The county grand jury that indicted the policemen is investigating 17 other officers who were present at the beating, which took place after King was stopped for speeding. A bystander captured the attack on videotape.

With Garcia's resignation, the Police Commission was reduced to three members. It has two vacancies.

Mayor Tom Bradley, who appointed Garcia in October, said he tried to talk him out of quitting but Garcia wanted to dramatize the need for a change in the city charter "that will make clear who is in charge of the Police Department."