By Brian Lowry, CNN

(CNN) -- Intense and disturbing, "Detroit" aspires to present-day relevance by chronicling a tale of racial injustice that's a half-century old. Yet the line drawn from those harrowing events to today is partially muddled by a misplaced focus, dwelling on a night of brutal police violence but shortchanging its equally significant aftermath.

Director Kathryn Bigelow and writer Mark Boal bring the same visceral style that informed their war collaborations "The Hurt Locker" and "Zero Dark Thirty" to Detroit in 1967. In interviews, Bigelow has cited the Michael Brown killing and subsequent unrest in Ferguson, Missouri as inspiration.

The story on which the movie is based, doubtless unfamiliar to many, is horrifying. After days of rioting and looting, police -- skittish about reports of snipers -- terrorized and killed African-Americans unluckily brought together at the Algiers Motel, as complicit National Guardsmen stood by.

The film has pieced together its own version of that history, incorporating a closing disclaimer that acknowledges elements of dramatization in areas where the record is murky.

The known facts, however, are terrible enough that Hollywood embellishment isn't responsible for 'Detroit's" shortcomings; rather, the film dwells so long on the ordeal experienced by those held at gunpoint -- as police vainly sought a perpetrator where none existed -- that the bigger picture nearly gets lost in the unsettling circumstances of what transpired.

The structure also somewhat blunts a solid cast because, with a few exceptions, we learn little about them. Key players include "Star Wars: The Force Awakens'" John Boyega as a security guard attempting to deescalate the tensions, Anthony Mackie as a just-returned Vietnam veteran and Algee Smith as part of an up-and-coming R&B group caught in the wrong place at the wrong time.

British actor Will Poulter, meanwhile, plays the most sadistic of the cops, who pressures and cows his peers into playing along, which includes participating in a perverse "death game" designed to coerce their suspects into giving up information that they don't have.

Bigelow is a gifted filmmaker, and it's bracing to see her war-honed cinematic technique applied to a domestic setting. But there's a herky-jerky aspect to "Detroit" that goes beyond the camerawork, as the narrative careens among its characters without fleshing them out, before becoming a horror movie once the claustrophobic motel encounter begins.

Part of that has to do with the inherent chaos of the situation. Still, Bigelow and Boal's efforts to place what happened in a wider context -- from opening animation depicting the migration of blacks to northern cities to the riots' precipitating incident -- don't clarify it much.

In hindsight, the beginning and end also feel somewhat rushed, ostensibly to present the policemen's viciousness in painstaking detail. That structure, however, speeds through the justice system's involvement, which is arguably the film's most lingering and resonant aspect.

Flaws and all, "Detroit" is still well worth seeing -- shedding a sobering light on an extreme case of criminality under the color of authority, while seeking to connect it to victimization of African-Americans, and young men in particular, which echoes beyond this snapshot of history.

While it's possible to admire the film's passion and ambition, given the auspices "Detroit" is less accomplished than it could have been -- a vehicle that succeeds in Bigelow's stated goal of triggering a conversation but delivers as a movie in fits and starts.

"Detroit" opens in wide release on Aug. 4. It's rated R.