A local Al-Qaeda chief known as ''Imad the killer'' escaped in a pre-dawn breakout from an Iraqi police station on Friday, triggering a wild shootout that left 13 militants and Iraqi policemen dead. Imad Ahmed Farhan, who police say has admitted to murdering at least 100 people, is on the run with two other ''emirs'' or local leaders of Al-Qaeda who broke out of their cells in a police station in the western city of Ramadi