Errol Morris calls himself a “director-detective,” and The Thin Blue Line uses interviews and official court records to examine the murder of a Dallas police officer. The film caused the official verdict to be overturned and an innocent man to be set free. Alternating between hilarity and sadness, the film intertwines documentary and fictional techniques to expose injustice. It is a tour de force as a comedy of truth. Morris presents the facts in a seemingly deadpan manner, yet he is dreamily obsessed with each detail. The music of Philip Glass enhances the dream.