The murder mystery in "Thun-derheart" will be easily solved by audience members about halfway through the film, and they may well spend the next hour wondering why the hero can't figure out who the central bad guy is.

But it doesn't really matter. The mystery is just surface plot material. There's a lot more going on in "Thunderheart" that makes it well worth the trip — not the least of which is the performance of co-star Graham Greene, fresh from his Oscar-nominated "Dances With Wolves" triumph, wonderful as a wise-cracking American Indian cop.

"Thunderheart" is the story of an FBI agent who is one-quarter-Indian, played by Val Kilmer. He has never come to terms with his heritage — he's pure anglo, happily living the life of a city fed.

So, it is with some chagrin that he accepts an assignment to head out to a reservation in the Badlands of South Dakota where a murder has been committed. He's being sent simply because he has American Indian blood, and he's not happy about it.

On the other hand, he is pleased to be assigned as Sam Shepard's partner. Shepard is a veteran FBI agent with a reputation for being the best in the business. Kilmer, however, is a a trigger-happy, short-tempered, somewhat sullen hotshot who wants to get the job done by the book. He has a lot to learn.

And he will learn a lot, of course, including a voyage of self-discovery that will encompass his American Indian background. And he will find that life on the reservation is much more volatile than he ever imagined.

Meanwhile, tribal cop Greene baits him, calling him "Little Weasel" and trying to get under his skin. But Greene recognizes that there is something inside Kilmer, and there may be a reason he's been sent there.

This leads to Kilmer striking up a reluctant relationship with the tribe's medicine man (Chief Ted Thin Elk) and an activist who is also a single mother (Sheila Tousey). These and others are supporting characters we come to care about, filling out the film in a way we don't often see in modern movies.

Though his script is weak in its mystery, John Fusco ("Crossroads," the upcoming "The Babe") and director Michael Apted ("Class Action," "Coal Miner's Daughter") create a rich backdrop, with fascinating character development and a serious focus on the spirituality of Indian beliefs. The result is a sometimes humorous and often thoughtful film with more depth than you might expect.

Kilmer is good in the lead, which follows his expert portrayal of Jim Morrison last year in the otherwise dreary "The Doors," but Greene and other American Indians in the cast (many acting for the first time) run away with the picture.

"Thunderheart" is rated R for some rough violence and profanity, along with some vulgarity and fleeting nudity.