The Trials of Los Angeles Police Officers' in Connection with the Beating of Rodney King.
It seemed like an open-and-shut case. The George Holliday video, played on television so often that an executive at CNN called it "wallpaper," showed three Los Angeles police officers--as their supervisor watched-- kicking, stomping on, and beating with metal batons a defenseless African-American named Rodney King. Polls taken shortly after the incident showed that over 90% of Los Angeles residents who saw the videotape believed that the police used excessive force in arresting King. Despite the videotape, a jury in Simi Valley concluded a year later that the evidence was not sufficient to convict the officers! 
Within hours of the jury's verdict, Los Angeles erupted in riots. When it was over, fifty-four people had lost their lives, over 7,000 people had been arrested, and hundreds of millions of dollars worth of property had been destroyed.