From Wikipedia

Incident at Oglala:
The Leonard Peltier Story

Incident at Oglala is a 1992 documentary by Michael Apted, narrated by Robert Redford. The film documents the killings of two Federal Bureau of Investigation agents, Coler and Williams, on the Pine Ridge Indian Reservation in 1975, and the legal case surrounding the subsequent trials of Robert Robideau, Darrell Butler, and Leonard Peltier. Peltier was convicted of murder, but many, including the International Indian Treaty Council, believe Peltier is innocent of the crimes. Apted was nominated for the Critics Award in 1992 for this film.