Sean Penn's executive producer debuts "Witch Hunt," an engrossing indictment of the American justice system presented through the eyes of a tiny community. Bakersfield, California voters elected a district attorney who was strong on crime for more than 25 years. He convicted dozens of innocent working-class mothers and fathers during his tenure. They spent decades in prison before being exonerated. He remains in office until the present day. On a local level, this scenario parallels what has occurred in the United States during the last eight years. When authority is permitted to exist unchecked, civil liberties are jeopardized.