LOS ANGELES -- A Los Angeles School Police Department officer was convicted Thursday of sexually assaulting a 21-year-old woman during a traffic stop.

Ian King, 34, was found guilty in connection with a May 3, 2007, traffic stop of an Orange County woman who was lost near Adams Boulevard and Sycamore Avenue in Los Angeles.

King -- who was in uniform in a marked car -- told the woman she had made an illegal U-turn and he needed to search her, said Deputy District Attorney Renee Korn.

A passing motorist who saw the officer with his hand up the woman's skirt wrote down the patrol car's license plate number and reported the incident to police, the prosecutor said.

The victim also called 911 within about 15 minutes, Korn said.

An eight-man, four-woman jury deliberated about two-and-a-half days before finding King guilty of one count of sexual battery by restraint and two counts each of penetration by a public official and sexual penetration by force or duress.

The young woman was "incredibly credible" and the evidence against the officer "overwhelming," Korn said.

"I think justice has truly prevailed here," she said.

King's attorney, Bill H. Seki, said he believed the defense had presented evidence that "established reasonable doubt throughout the case" that "collectively raised overwhelming doubt."

"To the moment I last saw him, (King) maintains his innocence," he said.

King was charged last May and taken off duty.

"Because of his conviction today, the district will immediately begin an official dismissal process against Mr. King," said Ellen Morgan, a Los Angeles Unified School District spokeswoman.

King had been free on $250,000 bail, but following the verdict, Los Angeles Superior Court Judge Marsha N. Revel ordered him to be taken back into custody.

He faces up to 20 years in prison when he is sentenced March 25.