 While the FBI investigated the case and arrested two suspects in November 1964, the district attorney concluded that there was insufficient evidence for prosecution.The case was dropped by local authorities, some of whom were complicit in the crime, according to FBI and HUAC documents.In June and July 2004, while preparing to shoot another documentary in Mississippi, Ridgen stumbled across a sequence that troubled him in a 1964 16 mm film produced in Mississippi by the Canadian Broadcasting Corporation.