Denzel Washington, so authoritative a hero in movies like Crimson Tide, Malcolm X, Courage Under Fire and Glory, takes on a rare bad-guy role in Training Day, and brings just as much fire to one of the nastiest cops in recent moviedom. The offbeat pairing of Washington and Gen-X favorite Ethan Hawke works splendidly in this gritty thriller about corruption in the L.A.P.D., even if David Ayer's script sometimes strains credibility.

Washington is absolutely riveting as Alonzo Harris, a veteran detective sergeant on the narcotics beat on the meaner streets of L.A. The movie, which takes place over the course of one day, follows Alonzo's initiation of Jake Hoyt (Hawke), a relatively naive but committed rookie who is being considered for a position on Alonzo's elite team. The pair first meet in a coffee shop ("Patrol fairies go to roll call," Alonzo scoffs), where the sergeant immediately starts taunting the rookie. No sooner do they hit the road when it becomes clear that Alonzo is a loose cannon; he terrorizes some college kids trying to score some grass, and forces Jake at gunpoint to sample the contraband, which is laced with PCP. Reeling from the drug, Jake is taken on a colorful tour which includes a stop at the home of a grizzled dealer (Scott Glenn) who warmly welcomes Alonzo, and the pursuit of a wheelchair-bound drug connection (rapper Snoop Dogg). Alonzo shows his contempt for the people he's supposed to serve when Jake spots a rape in progress and tangles with the assailants while Alonzo simply looks on. "Let the garbagemen handle the garbage," the veteran advises. Meanwhile, Jake can see the hate in the residents' eyes when Alonzo stops to visit his lover, who lives in one of the city's most dangerous neighborhoods.

Ultimately, we learn that Alonzo hasn't been hazing this young recruit just for a laugh. The sergeant owes a huge amount of money to Russian mobsters, and he's masterminded a big score that involves murder and the blackmailing of Jake. When Jake resists, it becomes very likely this "training day" will be his last.

Directed by Antoine Fuqua (Bait, The Replacement Killers), Training Day is so good with documentary-like detail and atmosphere, it's a shame that old-fashioned thriller plot mechanics need to be part of the mix. The edgy first half of the movie, as Alonzo and Jake tool around the streets of L.A., is much more persuasive than the second half, which includes a ridiculously unlikely coincidence that saves Jake from certain death. It's also slightly comical to watch the imposing Washington and the rather slight Hawke engage in a brutal climactic fight; it's like one of those wildly mismatched "Celebrity Death Matches" on MTV.

It's Washington who salvages those final scenes, taking his megalomaniacal character to a new level of monstrosity. Throughout, the actor projects such supreme arrogance and cool charisma, you easily forget the nobility of his other screen performances (although that same fierceness certainly pulsated through movies like Malcolm X, The Hurricane and Glory). Hawke, who also gives an impressively energetic performance in this fall's Tape, successfully moves beyond his callow image and convinces us he has the makings of a dedicated young cop. Director Fuqua, who comes out of music-videos, also gets entertaining turns out of rapper Snoop Dogg, and soul singer Macy Gray as an irate victim of Alonzo's scams.

--Kevin Lally