From "Psycho" to "The Boston Strangler" and beyond, the wild world of celluloid serial killers is peopled by split personalities. The two Tonys -- Perkins and Curtis -- gave their greatest performances as warped variations on the Jekyll-and-Hyde theme. But director Bruce Evans plays a less conventional game: His Jekyll's Hyde seeks a whole different co-star as well as persona.

With the double-shooting of some scenes and with their dialogue, William Hurt, left, and Kevin Costner bring a psychological twist to "Mr. Brooks." Click photo for larger image. 'Mr. Brooks' Starring: Kevin Costner, William Hurt, Demi Moore, Dane Cook Director: Bruce A. Evans Rating: R for strong bloody violence, some graphic sexual content, nudity and language Web site: www.theressomethingaboutmrbrooks.com/

"Mr. Brooks," a stylish psychological thriller about a man and his murderous alter ego, stars Kevin Costner in the title role. Earl Brooks is a philanthropic pillar of his community, a loving husband and father with a beautiful wife, a nifty house, a successful business -- and a dark secret (is there any other kind?).

We first meet the Brookses as they drive home from a ceremony honoring Earl as the Portland Chamber of Commerce's Man of the Year. Their casual conversation is suddenly joined by a third voice from the back seat -- heard and seen (in the rearview mirror) only by Earl.

It is Marshall (William Hurt) -- the Hyde side of Brooks -- whose Mephisto-like mumblings let us know that Earl is a murder addict, the infamous "Thumbprint Killer," who leaves his victims' prints smeared in their own blood at each crime scene. For two years now, Earl has sworn off serial-killing and attended AA meetings to curb his compulsion, but Marshall's insidious persuasion sets him off again -- "for one last time."

The resulting brutal double murder, however, is photographed by young Mr. Smith (Dane Cook) from a building across the way. Smith's subsequent blackmail attempt requires Earl to take him along for sick kicks on the "next" killing, while tough detective Demi Moore doggedly pursues the case -- and Earl.

The story, from the team (Evans and Raynold Gideon) that brought you "Stand By Me," is a good one. But it's the two lead performances that make the film work. Costner's normally flat tone and reticence are an aid rather than drawback here, intriguingly atypical and ambiguous. Were he a flashier, more charismatic actor, the contrast between his Jekyll and Hurt's Hyde -- his public life and private heinous deeds -- would not be so strikingly creepy.

But if you're like me, I suspect Bill Hurt will be the one who steals your focus. This intense actor has so many superb portrayals to his credit -- "Body Heat," "Gorky Park," "Kiss of the Spider Woman," "Broadcast News," "The Accidental Tourist," "A History of Violence." To those, add this newly fascinating one. He's not so much the evil twin as the killing-addiction itself -- the ever-so-supportive, cajoling id who eggs on Earl's ego. They're two sides of a twisted coin, but Earl's placid yin is no match for Marshall's malevolent yang.

Says Hurt to Costner, ominously, of blackmailer Cook: "Even if that guy were charming and funny, I still wouldn't like him."

You gotta love his delivery. Trivia buffs may recall that Costner (now 52) and Hurt (57) briefly crossed paths at the start of their careers in "The Big Chill" (1983). A quarter-century later, it's high time they reunited as The Diabolical Odd Couple. Their impact benefits from Evans' decision to double-shoot many scenes -- with Hurt in and out of the frame -- providing the option to include or exclude mad-mentor Marshall in the editing later.

Aside from Dane and Detective Demi, the dubious subplot concerns Mr. Brooks' nubile daughter, Jane (Danielle Panabaker), who may or may not have inherited a few of Daddy's undesirable genes. Only time -- and the ending -- will tell if she's a chippie off the old psychotic block.