Some ink-black stories can thrill; others can turn your stomach. The Killer Inside Me is a film noir so steeped in ugliness—no vampire or werewolf cuddliness here—it’s difficult to enjoy on any level. Based on a novel by Jim Thompson (and co-written by director Michael Winterbottom), the film starts stylishly, with “Fever” accompanying 1950s-decked-out stills of the cast. Baby-but-crazy-faced Texas sheriff Lou Ford (Casey Affleck) is sent to scope out a hooker, Joyce (Jessica Alba), and advise her to get out of town. She gets angry and starts slapping him, and he eventually hits her back. And then the sick but laughable happens: They pause, stare at each other, and start going at it, the highlight of their coupling being the belt with which Lou whips her.

Twisted behavior from a man of the law who doesn’t carry a gun and plays classical piano (he’s complicated!), but Lou’s S&M proclivity turns out to be tame compared to what follows. Lou also has a real girlfriend, Amy (Kate Hudson), who, it seems, initially has no idea that her beau would love to beat her ass. Both she and Joyce soon find out how screwed up the man they coo over really is. (At one point, Lou and Joyce exchange “I love you!”s while he’s punching her senseless.) And the audience finds out that Lou’s highly sexualized childhood turned him into an abuser young, and that there’s apparently nothing he won’t do to score a wad of cash or get revenge on someone who wronged him.

Even with flashbacks and Affleck’s mumbly narration, Lou’s motives are never quite clear. You might argue that he’s a fan of chaos, like The Dark Knight’s Joker or No Country for Old Men’s Anton Chigurh, but even that theory is iffy. Instead, The Killer Inside Me proceeds with one brutality after another, which makes it worse than vulgar—it’s just dull. And Winterbottom doesn’t spare the audience a drop of blood, lingering on unconscious, beat-up bodies long after viewers will get the point.

Affleck, at least, makes a fine psycho, albeit one who’s essentially a reprise of his The Assassination of Jesse James by the Coward Robert Ford character. He can simultaneously appear both innocent and loony; polite and barbaric. But such nuance is represented only in Lou and not in the film as a whole. Unlike Lou’s above-mentioned filmic brethren, this is one killer who won’t become iconic.