In early November, 2014, Craig Futterman, a law professor at the University of Chicago, got a call from someone who worked in law enforcement in that city. The caller told Futterman about a squad-car dashboard-camera video from a few weeks earlier, which showed a police officer shooting to death a seventeen-year-old boy named Laquan McDonald. According to the source, the video was at striking odds with the version of the incident that the Chicago Police Department had presented. In that account, the officer, Jason Van Dyke, acted in self-defense: McDonald was out of control and menacing him with a knife, so he shot him once, in the chest. But the source, describing the video frame by frame, evoked what sounded to Futterman like “an execution.”

Fifteen years ago, Futterman founded a legal clinic at the university focussed on civil rights and police accountability. He and his frequent collaborator, Jamie Kalven, who runs a nonprofit journalism project called the Invisible Institute, interviewed witnesses, and they corroborated what the caller had said. Last December, Futterman and Kalven called on the C.P.D. to release the video. Soon afterward, Kalven, through a Freedom of Information Act request, obtained the autopsy report. It showed that McDonald, a ward of the state who had “Good Son” tattooed on one hand, had been shot sixteen times.

For months, the C.P.D. refused to release the video. There were protests. Then, last summer, Brandon Smith, a freelance journalist, sued the department to make the footage public, and a judge ruled in his favor. On November 24th, the day Officer Van Dyke was charged with first-degree murder, and thirteen months after the shooting, the police department finally released the video. It shows McDonald trotting briskly away from officers as they approach, not menacing them. When Van Dyke’s first shots hit him, he spins and drops to the ground. An officer kicks a knife away. No one is seen offering first aid. Last week, the Justice Department announced that it is opening a wide-ranging investigation into the policies and practices of the Chicago police. Mayor Rahm Emanuel, who resisted making the video public, and who criticized the Justice Department investigation as “misguided,” said last Wednesday that he now welcomes it, and apologized for McDonald’s death.

This is not the first time that Futterman has received an inside tip about police abuse. He believes that the whistle-blowers represent “the majority of Chicago cops,” who are doing their jobs “just as you would want them to.” Those officers “hate this stuff” as much as anyone, because “it creates hostility to the police, and steals the honor of those who are doing things right.” Yet even the best-intentioned officers have to cope with a code of silence—the mirror image of the criminals’ code against snitching.

In the McDonald case, the first officers on the scene, responding to a call about a young man acting erratically and breaking into trucks, were doing things right. McDonald apparently did have a knife, and, according to the autopsy, he had PCP in his system. Futterman said that those officers were careful. They “needed to arrest him, take him to the hospital,” and “they called for backup, for someone with a taser.” Then Van Dyke arrived and instantly fired sixteen shots. In reports to internal investigators, the other officers either corroborated his story or said that they hadn’t seen what happened. One said that she had been looking down and missed the whole thing.

The code of silence has protected some particularly reprehensible behavior in the C.P.D., much of it directed at the city’s black population. Perhaps the most egregious was that of Jon Burge, a commander who, in the nineteen-seventies and eighties, headed a group of officers that he called the Midnight Crew. To extract confessions, the crew tortured dozens of men, most of them African-American, using electric shock, suffocation, and Russian roulette. Last May, the city agreed to a reparations agreement that included $5.5 million for the victims and an obligation to teach the episode in the public-school curriculum. According to the Better Government Association, between 2010 and 2014 there were seventy fatal shootings by the Chicago police, a higher number than in any other large city. (Phoenix, Philadelphia, and Dallas had a higher number per capita.) Between 2004 and 2014, the city spent $521 million defending the department and settling lawsuits claiming excessive force.

Last March, after a seven-year legal battle, waged by Futterman, Kalven, and two Chicago law firms—Loevy & Loevy and the People’s Law Office—to obtain records of police officers who had accumulated repeated citizen complaints, an Illinois appeals-court judge ordered the records released. They show that, of nearly twenty-nine thousand allegations of misconduct filed between 2011 and 2015, only two per cent resulted in any discipline—and, of those which did, the vast majority took the form of reprimands or suspensions of less than a week. Moreover, while African-Americans filed most of the complaints, those lodged by whites were more likely to be upheld.

Emanuel’s belated apology and the Justice Department investigation represent progress, but the real hope is for an end to the code of silence. Officers who come forward have to be able to do so without fear of losing their jobs, or worse—in 2011, a cop named Jerome Finnigan pleaded guilty to plotting to kill a fellow-officer who he suspected would testify against him. Lifting that fear will require the department and the city to first accept the transparency that they have often resisted.

Thanks to the efforts of Futterman and Kalven, among others, anyone can now search an online database called the Citizens Police Data Project. It shows that, before Finnigan and Van Dyke were charged with serious crimes, there were sixty-eight complaints against Finnigan and eighteen against Van Dyke. (Neither was disciplined.) Meanwhile, the Fraternal Order of Police has sued to block the release of more data, citing a stipulation in its contract that calls for destroying any disciplinary records older than five years. Among the records are those of some of Burge’s crew; there are still torture cases pending against them. For the citizens of a community to trust the police, they have to know that they aren’t being systematically lied to. It’s a simple lesson that activists around the country have been reminding us of, but the Chicago police seem to have to learn it over and over again. ♦