U.S. District Judge John F. Walter on Saturday ordered the Times to delete certain details from an article about a Glendale police detective accused of working with the Mexican mafia.
The Times said they will contest this order, calling it an unusual violation of the First Amendment.
"We believe that once material is in the public record, it is proper and appropriate to publish it if it is newsworthy," Norman Pearlstine, executive editor of the Times, said.
The defendant, John Saro Balian, pleaded guilty on Thursday to lying about his involvement with organized crime, accepting a bribe and obstructing justice, the Times reported.
The judge granted Balian, 45, a restraining order against the newspaper on Saturday, but the article had already gone to print.