If there’s a defining metaphor in the works of novelist James Ellroy, it’s the specialized prostitutes that populate his LA Confidential. Recruited because of their resemblance to 1940s screen goddesses, the women were an attempt to give men a chance to live the fantasy, even as they submitted to their basest urges. That’s Ellroy’s world: a Hollywood where the glossy surface illusion hides all the ugliest parts of human nature.

This is why there may be no worse choice to direct a James Ellroy adaptation than Brian DePalma. Over a 40-year career behind the camera, DePalma has built a reputation as the master of a slick image. Even in the lamest of vehicles—Snake Eyes, anyone?—there would always come a moment in a DePalma film where you’d be distracted at least momentarily by a virtuoso camera maneuver or a thrilling set piece.    

So here’s DePalma, taking on the lurid underworld of Ellroy’s fiction and turning it into a flourishy exercise in high-camp pseudo-noir. The events are based on a true-life 1947 Los Angeles murder case, involving the discovery of the mutilated corpse of a beautiful woman. Warrant cops Bucky Bleichert (Josh Hartnett) and Lee Blanchard (Aaron Eckhart) happen to be on the scene when the body of Elizabeth Short—quickly dubbed “The Black Dahlia” in the press—is discovered, and are temporarily reassigned to homicide. Bleichert soon realizes that Blanchard’s obsession with victimized young women—like Kay (Scarlett Johansson), with whom he lives in an unconsummated romance—could complicate their investigation. And once he realizes that Madeleine Linscott (Hilary Swank) could be involved in the case, things get even more complicated.

For at least a little while, it looks as though Josh Friedman’s radically condensed adapted screenplay is going to hit all the important notes. DePalma, however, isn’t about to let anyone forget that this is his movie. The first discovery of the body is part of a showy crane shot, quickly followed by a deep-focus composition of the two cops in a doorway. Bleichart’s introduction to the Linscott family becomes a single take from Bleichert’s point of view.

Nearly everything that’s remotely interesting about The Black Dahlia comes from its stylized moments. Swank takes her femme fatale spot over the top, creating a character of only vaguely recognizable humanity. The film’s funniest scene is also one of its looniest, a dinner at the Linscott mansion that involves a rant by the doped-up matriarch (Fiona Shaw) and ends with the sound of a cuckoo clock.

In a way, you can’t blame DePalma for trying not to be bored. Fundamentally, James Ellroy’s Black Dahlia could not be less about figuring out who killed Elizabeth Short; this is, after all, an unsolved true crime we’re dealing with. Yet for its last hour, this screenplay plods forward on plot-machine autopilot, as though nothing matters but the procedural details of cracking the case. Every bit of subtext gets stripped away, leaving a conclusion full of shrieking confessions and unsatisfying resolution. That’s the irony of The Black Dahlia: In an effort not to leave a tedious mess in his wake, DePalma shakes the audience awake by re-applying all the Hollywood artifice James Ellroy spent his career trying to strip away.

THE BLACK DAHLIA ( * * )

Directed by Brian DePalma. • Starring Josh Hartnett and Scarlett Johansson. • R, 121 min. • At Maya Cinemas, Northridge Cinemas.