"Bullock's a good cop!" I kept expecting someone to proclaim, T.J. Hooker-style, throughout this tedious excuse for a thriller, as she steadfastly maintains that the gruesome murder she and her partner are investigating could not have been committed by their prime suspect. Instead, she believes the perps are two high-school students trying to mess with the cops' minds by leaving false clues and generally behaving as if they've read profiling textbooks, which they have. Never mind that it's unlikely that any two kids -- particularly this floppy-haired, absinthe-drinking, death-obsessed gothy-poseur type and this scarily psychotic popular guy -- could pull off a sophisticated murder like this one as their first crime. What's bad is that there's no mystery: we know they did it, and Bullock and Chaplin cannot hope to make the process of investigation even mildly interesting. But the movie's not entirely useless -- it could be an insomnia aid.

Sandy's a tough cop, the one the guys call "the hyena" and "the scorpion," which draws her typical vacant stare in reply. She seduces her partners as a hobby, then throws them away when she's finished with them, as Whatshisname-boring-and-British (though he's American here) discovers. See, Sandy is Tormented by something in her past, but the only evidence we have of this is the bald assertion of such. Bullock (Practical Magic, A Time to Kill), bless her, may be a nice girl, but she just doesn't have the wherewithal to do Haunted -- squinting a lot doesn't do it. So when she makes her advance on Whatshisname-boring-and-British, it comes completely as a surprise, to him as well as us, because we just can't see anything seething at all beneath Sandy's blank exterior. There may well be something Hidden Deep Inside Her that makes her use men and then reject them, but her Cassie Mayweather plays like an unintentional parody of misbehaving men, and her awkward seduction of Whatshisname-boring-and-British's (Lost Souls, The Thin Red Line) Sam Kennedy feels like a hack screenwriter's desperation: Time for beat, time for a sex scene.

Ryan Gosling (The Believer) and Michael Pitt (Finding Forrester) are game as the murderous teens, but Tony Gayton's screenplay undermines the appropriate coldness of their performances by casting their deeds like something out of I Know What You Did When You Were Supposed to Be Studying for Your Calc Exam, reducing a horrendous crime to little more than peer pressure and teen rivalry run amuck. And when Gosling turns his psychopathic charm on Sandy, things just go from boring to bad: Her inability to muster any inner resources turns her character from someone who's supposed to be a capable cop into a whimpering pansy, a grown woman who is disarmed by a smarmily charismatic teenager. He attacks her, she responds in kind, and then she's worried that she may have given him a boo-boo. Slap those cuffs on him and haul in him for assaulting an officer! But no -- she just collapses in tears that seem to come from nowhere.

Murder by Numbers wants us to root for Cassie, and instead it makes us wish for her demise by the time we get to the damsel-in-distress ending. I wish I could ask for Sandy's gun and badge. She's an unintentional menace to moviegoers.