In the wake of tragic, violent crimes, there's a ubiquitous, easy, and simple response: shake your head, look downcast, and intone in a very mordant tones, "What sort of person would do a thing like that?"

What's not ever supposed to happen, is somebody actually going out and answering that question, and that's the most outrageous, stunning, wonderful thing about music video director Alexandre Moors's feature debut, Blue Caprice. Here is a film that casts its eye upon the horrifyingly random sniper attacks in the Washington, D.C. area in 2002, and attempts to answer questions that aren't polite to talk about in a media landscape that much prefers to partition criminals and killers into the Bad People bin, so broken and devious that you cannot possibly think of them as human. Questions like, where did the two killers come from? What was driving them? How did they come up with their schemes? Who were they?

This is absolutely not the same as trying make excuses or justifications for John Muhammad and Lee Malvo - the film pointedly eschews surnames - like some of the more outraged negative response to the film have made it out. If anything, Blue Caprice is more troubling and disturbing as a direct result of allowing John and Lee to emerge as undeniable human beings: when we can write off every single murderer and villain in the world as some kind of bogeyman, we aren't obliged to grapple with the reality that actual people like the sort you see at the store or on the street are, in fact, capable of doing unbelievably terrible things when just one little thing goes wrong in their head.

The things that go wrong for 17-year-old Lee (Tequan Richmond) have an easily-pinpointed cause, at least as Moors and screenwriter R.F.I. Porto have it (the film hardly pretends to be a docudrama): he was homeless, without a parent, and far away from his native Jamaica when he met John (Isaiah Washington), the best father figure immediately available to a kid who needed a father figure right now. Unfortunately, in addition to having a kindly eye on the boy, John suffered from a hell of a persecution complex, in which an indefinite Them was responsible for everything wrong in his life, from the difficult time he had buying guns to the way his ex-wife mysteriously had a problem with him kidnapping their children and traveling to Antigua. Fed a steady stream of misogynistic, anti-social, paranoid ravings from the charismatic man who was the only person whose love and approval he craved, Lee naturally and inevitably drifted into anti-social freakouts of his own. Eventually, whatever thin dam was holding John in check broke, and that's how you get a cross-country trip from Washington state to Washington, D.C. that left 27 people dead or wounded.

Blue Caprice is not "about" the murders, which occupy less than a third of its 90-minute running time, and are presented as a chronologically imprecise, impressionistic series of elliptically-staged images (which isn't to say that they don't have potency: the first murder Lee commits is presented as a close-up of his face with just a small splash of blood on it, and Richmond's staring, open-mouthed expression is as unnerving as all the split-open dummy heads in all of horror). It is much, much more about the way that a murderous psychology is nurtured, developed, and intensified, presenting the relationship between John and Lee as a bubble (only sometimes punctured by a deranged-in-their-own-right married couple played, unexpectedly, by Tim Blake Nelson and Joey Lauren Adams), in which they are able to live only in their own stewing fantasies of oppression. This is carried off with excellent skill by the filmmakers, whose grey- and blue-dominated color palette and frequent overcast lighting (the cinematographer was a certain Brian O'Carroll, whose career I look forward to following) add an unmissable sepulchral feeling to the already nasty content; and it must be said that the acting is pretty incredible, as well. Particularly from Washington, whose reined-in portrait of raging paranoia is wonderfully unexpected and effective, more about the immensely slow burn of his character than grabby "I am a psycho!" showboating.

Not everything is flawless: the movie has all the feel of an ambitious, overreaching first feature, with many individual moments that probably wouldn't happen if a little more discipline and judgment was available on-set. There is a particular scene, in which Lee and John are in a car during a rainstorm, and the droplets are shadowed on their faces: it's showy and pretty and complex, but also remarkably corny and unoriginal, while proving an especially anti-subtle moment in a film that thrives on its subtleties. And there's the usual gamut of little misjudgements in the hand-held camerawork, which is indifferently and arbitrarily applied; and in the staccato editing pattern, which especially near the beginning make it all too clear that Moors got his start editing videos. There's a lot of style that just doesn't cohere, throughout the movie, and plenty of times where the atmospheric, tone-poem feeling of the whole shades into some kind of misery-camp mush.

Even more than in most movies, though, what emerges from Blue Caprice isn't the excellence or hamminess of any individual shot or scene, but the feeling of the whole thing overall; the way that the aesthetic creates an almost Biblical feeling of potential destructive energy, and the way that the two leads reveal deeper and more horribly blanked-out registers of amoral detachment as the film progresses. The longer we spend in their heads, the more uncomfortable the film is to watch, which is obviously the exact point of the thing; to plunge the viewer right into the blackest heart of darkness. Ultimately, the filmmakers can't truly communicate what sort of people Lee and John were during their crime spree, and the editing turns increasingly disjointed near the end in a not entirely effective attempt to make their unknowable natures part of the aesthetic and not simply a limitation. Still, we get awfully close to who they are and what that means, and it is by no means a pleasant or enjoyable experience. But for the viewer willing to undergo that kind of nastiness in pursuit of a greater understanding of every kind of human behavior, it's certainly a rewarding and memorable piece of cinema.