Chicago police officer Jason Van Dyke, who faces murder charges after shooting Laquan McDonald, had at least 17 citizen complaints against him, according to a University of Chicago database of police records. Here's what else the records show about complaints against Chicago cops. (Gillian Brockell/The Washington Post)

THIS TIME in Chicago, the police coverup failed.

Until Officer Jason Van Dyke was charged Tuesday with first-degree murder for shooting a teenager, Laquan McDonald, 16 times last year, it was almost unheard of for a Chicago police officer to be held accountable in a shooting incident, whether or not a suspect died. Like Mr. McDonald, most of the victims are black.

The problem starts in the mayor’s office; implicates the police department’s top brass, the police union and rank-and-file officers; and runs through the city’s nominally independent police review authority, which routinely dismisses allegations of police wrongdoing. Since 2007, the authority has reviewed nearly 400 police-involved shootings in Chicago, fatal and non-fatal — an average of about one per week — and judged just one of them to be unjustified. Just one officer was charged criminally in all those shootings, and he was acquitted.

Mr. Van Dyke’s lawyer said he will show in court that the shooting was justified. That will be challenging, given the police dashcam video, which shows Mr. Van Dyke, who is white, opening fire even as Mr. McDonald veers away from him and then falls to the ground.

The video is stomach-turning. Its aftermath lays bare a system with an utter absence of accountability. It also raises disturbing questions about the Cook County prosecutor, Anita Alvarez, and federal prosecutors. They had the incriminating videotape for months; why were no charges brought until this week?

Protesters shut down a street in Chicago Wednesday during a protest over the death of 17-year-old Laquan McDonald. (Paul Beaty/Associated Press)

Mayor Rahm Emanuel (D) fought to withhold the video from public view for months until a judge ordered it released. Then, rather than calling for reform in the police department, which fatally shoots more people than any other force in the nation, Mr. Emanuel suggested the episode arose from one bad apple.

That’s wrong. Chicago has many fine officers who do tough jobs. The city needs them; but it also needs a better department. It was the police who allegedly destroyed evidence by deleting videotape recorded by a nearby Burger King security camera — video that may have contained relevant footage — shortly after the McDonald shooting. It was the police who issued misleading information, saying Mr. McDonald was shot as he “continued to approach the officers.” It was the police who maintained a code of silence despite at least seven other officers who witnessed the shooting at close range. That’s outrageous and should lead to further criminal inquiries and the immediate firing of the city’s police superintendent, Garry McCarthy.

The problems are not about tactics and training; they’re about a culture of impunity, including a police union that routinely covers for even the dirtiest cops. At least 15 misconduct complaints had been lodged against Mr. Van Dyke over the years, none of which resulted in disciplinary action. In the decade ending in 2014, the city is estimated to have spent $500 million settling legal claims arising from police misconduct; that was before it paid $5 million to Mr. McDonald’s family this year.

Mr. Emanuel, appealing for calm, now says it is time for “healing” in Chicago. In fact, no real healing is possible without deep reforms in a rotten system.