As protests against the deaths of Eric Garner and Michael Brown at the hands of police spread across the United States, Nick Broomfield’s documentary Tales of the Grim Sleeper could not be more timely. Shortlisted for an Academy Award and coming to theaters December 19, the film documents the confounding apathetic investigation of an alleged Los Angeles serial killer, who has been accused of 12 murders between the mid-80s and 2010.

The man arrested was Lonnie Franklin, nicknamed “The Grim Sleeper” because it was initially thought he took a 14-year hiatus from killing. Though the L.A.P.D. realized a serial killer was targeting black women in South Central in 1985, they did not alert the community to that fact until 2007—after the murders had been occurring for 22 years.

Nick Broomfield, the 66-year-old Santa Monica–based British expat known for relentlessly probing true-crime docs such as Kurt & Courtney and Biggie & Tupac, sees the link between his film and ongoing national anxieties about law enforcement. “If you look at the statistics on [N.Y.P.D.] police shootings in the last 15 years, there are 179 police-related deaths, and only three of these led to charges, and only one led to a conviction,” Broomfield noted. “People in black communities don’t feel that there is a justice system that supports them. Children grow up in South Central believing that the police are the last people they should turn to if there is a problem. That's really what Tales of the Grim Sleeper is about.”

The L.A.P.D. refused to participate in the making of the film, which forced Broomfield to turn to members of Franklin’s community for help in understanding the man accused of being “The Grim Sleeper.” One friend claimed that he used to pick up women with Franklin, and that he knew about half of the 180 women whose photos were reportedly found inside Franklin’s house.

The only member of the community who stepped up to share her suspicions with the L.A.P.D., was Enietra Washington, a survivor of an alleged attack by Franklin. “Even when Enietra spoke to the police, after they found her shot in the chest . . . the police didn’t follow up on anything she said because they viewed her as a black crack head,” Broomfield explained. “She wasn’t on crack, but as she says, in their eyes every black woman is a hooker. Enietra was made to feel as if she had somehow committed a crime, rather than being a victim.”

The film is a true-crime investigation but also a portrait of the insular world of South Central L.A., a community striving to make due without significant governmental support systems. For Broomfield, it reveals a central irony. “The people who most need help can’t get it,” he says. “You know, so many members of this community are or have been addicted to crack—and once you're convicted of a felony, which possession of crack is, not only do you go to jail, but once you're out of jail you're not eligible for food stamps or for public housing, and it's very tough to get a job.”

The connection between the neighborhood’s poverty and the L.A.P.D.’s struggle to solve the case is the film’s live wire, prompting the viewer to speculate whether the delay in arresting Franklin was a matter of incompetence, apathy, or perhaps even worse. In the film’s most harrowing scene, Franklin’s son Christopher describes meeting L.A.P.D. officers who asked if they could shake his hand, aware that he was the son of the Grim Sleeper. Broomfield was dumbstruck by the revelation. “Christopher told me his father had a lot of fans in law enforcement. Some police officers actually admired Lonnie for ‘cleaning up the streets.’ That seemed, to me, too incredible—that a serial killer could be a person who was respected within certain sections of law enforcement.”

One of the most troubling pieces of information presented in the film is that police officers are reported to have used the unofficial acronym “N.H.I.” (“no humans involved”) to describe the slayings of prostitutes and drug addicts, such as the Grim Sleeper’s victims. “This film is a story of disposable human beings,” Broomfield said. “Certain sections of the LAPD perceive these people as their enemies. They consider them to be nonhumans, not in any way a useful section of the community. This behavior wouldn’t be tolerated for a minute in a white, affluent neighborhood . . . It’s easy for [the L.A.P.D.] to say, well, we’ve got Lonnie now. But they don’t want to answer why it took so long, because they can’t answer it. There is no way of answering it.”

Following its theatrical release via HBO Documentary Films, Tales of the Grim Sleeper will air on HBO in April.