An FBI man with Sioux background is sent to a reservation to help with a murder investigation, where he has to come to terms with his heritage. Slowly he rejects the intimidating tactics of his fellow FBI agents, who are not so interested in solving the crime as covering up an incriminating situation with the locals, and as he becomes more tuned to his heritage, the locals begin trusting him. Based on actual Reservation occurrences of the '70s. http://en.wikipedia.org/wiki/Thunderheart
Thunderheart is a 1992 contemporary western mystery film directed by Michael Apted from an original screenplay by John Fusco. The film is a loosely based fictional portrayal of events relating to the Wounded Knee incident in 1973.
Filming was done with the support of the Oglala Sioux people, who trusted Apted and Fusco to express their story.