In the early morning hours of Sunday, July 23, 1967, Detroit police raided an unlicensed social club, or “blind pig,” on the city’s Near West Side. The all-black clientele, who had been celebrating soldiers returning from Vietnam, were hauled away in paddy wagons, igniting five days of rioting. Stores were looted, cars and buildings burned. State troopers, the National Guard, and eventually two airborne divisions were called in. By the end, more than 7,000 arrests were made, and 43 people, mostly black, were dead.

The director Kathryn Bigelow’s Detroit opens with lightly animated variations on Jacob Lawrence’s painting series on the Great Migration, as onscreen text explains the deep roots of black Detroit’s discontent. Bigelow then dramatizes the raid on the blind pig and the outward ripple of violence through the city. A young John Conyers, then serving his second term in Congress, pleads with residents, “I need you not to mess up your own neighborhood.” We see footage of Michigan Governor George Romney, bearing an almost disconcerting resemblance to his son. A little girl peering out a window is mistaken for a sniper and shot dead. A baby-faced detective shoots a looter in the back and is informed by a superior that he may face murder charges. For a time, it appears that Bigelow, as she did in her superb and sophisticated Zero Dark Thirty, will tell a broad, multi-faceted story, the tale of a city that has become a war zone.

But she doesn’t. Working from a screenplay by her customary collaborator, Mark Boal, Bigelow instead quickly narrows her focus to a single building on the night of July 25th. The building is a detached house that served as an “annex” to the black-owned Algiers Motel. On the night in question, 10 black men and two white women were in the annex when nearby Guardsmen believed a sniper had fired on them from one of the windows. Along with Detroit police and state troopers, they shot out windows and then stormed the building. By the end of the night, three of the residents—all black men—would be shot dead, and the remainder beaten and humiliated.

Detroit is a powerful, harrowing film. Insofar as it seeks to place viewers in the shoes of its helpless, terrified victims of police brutality, it succeeds to an almost unbearable degree. But that is a strangely narrow ambition for a filmmaker of Bigelow’s gifts, not to mention a film whose title encompasses an entire city. What is missing is not merely scope, but nuance: Zero Dark Thirty and Bigelow’s earlier The Hurt Locker conveyed not merely the conflict between characters but also that within them. Detroit, by contrast, is purely a story of villains and victims, a horror movie made all the more horrible by the fact that it is true.

Inevitably, accounts vary concerning precisely what took place in the Algiers Motel annex that night. (John Hersey wrote a 1968 book trying to reckon with these inconsistencies called The Algiers Motel Incident.) Bigelow and Boal have done their best to recount the events as accurately as possible, but unlike Hersey they have to pick one story and stick with it. And the story they choose, though chilling and intense, is disappointingly one-dimensional in its portrayal of both the Algiers Motel residents and their police assailants. (In order to clarify the choices the filmmakers made, I will describe some of the historic and cinematic details; those concerned about mild spoilers, be advised.)

The apparent “sniper fire” was one resident fooling around harmlessly with a starter pistol. Although he was shot almost immediately after authorities stormed the building, the pistol was never recovered. Police then rounded up the remaining residents in a ground-floor hallway, among them a returning vet (the excellent Anthony Mackie), a doo-wop singer (Jacob Latimore), and the two party-seeking young women (Hannah Murray and Kaitlyn Dever). When the Guardsmen and state troopers leave the scene—the latter, sensing trouble, don’t want to “get involved in any civil-rights incident”—the residents are left at the mercy of three Detroit policemen. They are all, like the vast majority of the force at the time, white.

Two of the cops (played by Ben O’Toole and Jack Reynor) are clearly racist and comfortable with the use of violent force on civilians, in particular black ones. But the third (Will Poulter) is a sociopath out of central casting, right down to the Mephistophelean tilt of his eyebrows. Lest we have any doubt on this score, he is the same baby-faced officer whom we saw kill a looter without remorse earlier in the film. He is insistent that he will not leave the premises until a shooter is identified and the gun recovered. To this end, he and his partners line the residents up facing the walls of the hallway and proceed to use every brutal tool at their disposal: beatings, murder threats, mock executions, and ultimately (if, in Bigelow and Boal’s telling, somewhat accidentally), actual killings.

This scene in the hallway is the centerpiece of the two-hour-plus film, and it is nothing short of horrifying. The residents’ terror is palpable, as is the cops’ air of utter impunity. But the impact of violence in cinema is rarely cumulative: Each successive depiction may repulse, but over time they begin to numb as well. So it is with the hallway scene. What begins as a shocking portrait of police misconduct gradually becomes a test of audience endurance.

If this extended central act is problematic in narrative terms, it is even more so when it come to the film’s political message. Poulter’s diabolical cop, however accurate, tells us next to nothing about the cultural and institutional forces that fed racism and abuse in the city (for example, the lack of a civilian police review board, and a police “value system” that encouraged bigotry). He is evil, full stop, with no further context or explanation required.

Bigelow and Boal’s efforts to avert any hint of moral complication is made most apparent in their treatment of the most ambiguous figure in the story, Melvin Dismukes, a black private-security guard who was also present at the motel and, according to some witnesses, participated in the beatings. Detroit does not consider this possibility, instead presenting Dismukes (played with quiet charisma by John Boyega) as a good man in an impossible situation, a peacemaker who tries only to protect the motel residents. The film presents his subsequent prosecution—in extreme contrast to that of the white cops—as a gross injustice. And it does not mention at all that he, along with the cops, was found guilty by an informal tribunal of black city leaders that included Rosa Parks.

In Zero Dark Thirty, Bigelow and Boal embraced such moral complexities and contradictions. Indeed, the film was so nuanced that some viewers—egged on by self-interested critiques from Senators John McCain and Dianne Feinstein, among others—believed the film to be “pro-torture,” which it emphatically was not. (Always be skeptical when political figures present themselves as film critics: The former LBJ aide Joseph Califano similarly helped torpedo Selma’s Oscar chances with an op-ed in The Washington Post.)

It is easy to understand why Bigelow and Boal sought to avoid such ambiguities in Detroit—given both the ugly tensions of the current political moment and the ways in which Zero Dark Thirty was misconstrued. But the result is a film that, for all its emotional power, is strangely disengaged from the cultural and systemic forces that led to police brutality in 1967 and continue to do so today. It is an opportunity missed.