Errol Morris, known for his peculiar documentaries Gates of Heaven and Vernon, Florida, once entertained a rapt interest in criminal responsibility while a graduate student in philosophy at U.C. Berkeley. Reviving this passion, he traveled to Dallas to research a documentary on "Dr. Death," a psychiatrist who often served as an expert witness in capital crimes. But Morris became sidetracked by a story of one of the prisoners who'd been sentenced to die, at least in part because of the doctor's testimony. Randall Adams, convicted nine years earlier of a cop killing, sat on Death Row, declaring his innocence. Morris had his own conviction that a miscarriage of justice had been done. He then filmed interviews with Adams, lawyers, police involved in the case, witnesses, the jury, and the man Morris was sure had actually committed the crime. New evidence surfaced, making the film unfold like a classic thriller-only there's that disturbing ache that real lives are in the offing. "The Thin Blue Line is the ultimate paranoid dream," says Morris. "It's like my other movies in its style, but the stakes are much higher here-a man's life. It's the only film I know of where the investigation was actually done with a camera." Thanks to Morris' persistence and his admirable detection, Adams will soon be re-tried.