Hump Day Movie: Thunderheart (1992)
Thunderheart stars Val Kilmer, Sam Shepard, and Graham Greene. I think this is one of the first movies I ever saw Greene in, and it's definitely the one where I developed my crush on him.
Kilmer plays an FBI agent in the 1970s sent as a liason to an Sioux Reservation to investigate a murder because he is 1/4 Sioux. The problem is that he doesn't identify with his Native American heritage, and to the people on the rez, he's just another white man in a suit. Once he arrives, he discovers that there is far more going on than a "simple" murder. He steps into the middle of a war, and some machinations by greedy people that have turned the South Dakota Badlands into the murder capital of the country.
There is a bit of "Hollywood" to the story, but enough heart remains to make this one of the more memorable Kilmer movies. It's one I recently re-watched on Amazon Instant Streaming, and it's held up just fine. It's also available on DVD for around $6.
It is very violent, however, and more than a little disturbing given the subject matter. If you haven't seen it, you've missed out.