A NEO-NOIR thriller about a onetime gangster who emerges from a kind of self-imposed exile to "solve" his younger brother's suicide, "I'll Sleep When I'm Dead" is, at least by conventional standards, more sizzle than steak. But with sizzle this stylish and psychologically satisfying, who needs the red meat?

The meat, in this case, is the question of why small-time coke dealer Davey Graham (Jonathan Rhys-Meyers) would have slit his throat in the bathtub of his squalid British flat. You and I, of course, pretty much know why, since we've been shown the events leading up to his death early on in the film. Davey's big brother, Will, on the other hand, played with seething restraint by the great Clive Owen, does not. "Dead," then, is more or less the story of Will's journey toward an answer we already have figured out.

As thrillers go, the trip is straightforward enough. Surfacing after three years in hiding, during which he has been living out of the back of a rusty van in the woods, Will comes back to town, shaves, showers and otherwise pretties himself up from his mountain-man guise, and then methodically tracks down the mobster Boad (Malcolm McDowell), whose actions precipitated Davey's death. At the film's climax -- and this is no spoiler -- Will simply points a gun at Boad's head and asks Boad why he did what he did.

And then Boad tells him.

That's it. Yet that's also not it -- not by a long shot.

As another character in "Dead" says at one point, "When I say left, I mean right." Like him, the movie itself puts forth one thing, yet means quite another. If you're looking for the trajectory of a traditional mystery, one in which the "reveal" is saved only for the final frames, at which point the suspense goes slack, forget it. This one is as cut and dried as they come, despite the comment by Davey's cockney best friend, Mickser (Jamie Foreman) that, "No one knows what happened. It's a [expletive] mystery, innit?"

Well, no, it isn't really. Yet, when the screen goes dark, and the closing credits roll, far greater mysteries linger than the reasons for the death of one suicidal punk.

Yet, if it doesn't operate on the level of crime fiction, what is this thing? More akin to Greek tragedy, really, it's a look into a man's soul. And Will is its towering, inexorable, tragic hero, a man who, by seeking only those questions that he can find answers to, is merely doing everything he can to distract himself from the ones that he can't.

Directed by Mike Hodges, who worked with Owen in "Croupier," "I'll Sleep When I'm Dead" is less concerned with identifying the fall guy -- with finding someone to blame -- than with examining the fallout of our own actions. Ultimately, it's Will, not Boad, who, because of his disappearance from Davey's life, bears some of the responsibility for his brother's death.

In that sense, the spare and unsparing tone of "I'll Sleep When I'm Dead" makes it as existential -- and as original -- a whodunit as they come.

I'LL SLEEP WHEN I'M DEAD (R, 102 minutes) -- Contains obscenity, violence and drug use. At the Cineplex Odeon Dupont Circle and the AFI Silver Theatre.

Clive Owen is a gangster who comes out of hiding to look for answers to his brother's death in "I'll Sleep When I'm Dead."