President Barack Obama said he was "deeply disturbed" by the graphic video footage of the death in Chicago of a black teen shot 16 times by a white police officer.
The dash-cam video shows Officer Jason Van Dyke, who is white, shooting 17-year-old Laquan McDonald 16 times. Van Dyke was charged Tuesday with first-degree murder.
In a statement posted to Facebook on Wednesday night, Obama also said he is personally grateful to the people of his hometown —Chicago — for keeping protests peaceful. Local officials had worried that releasing the video would set off violent unrest like that seen in Ferguson, Missouri and Baltimore after the deaths of black men at the hands of police.
The relevant portion of the video runs for less than 40 seconds. Technical issues were blamed for a lack of audio.
McDonald swings into view on a four-lane street where police vehicles are stopped in the middle of the roadway. As he jogs down an empty lane, he appears to pull up his pants and then slows to a brisk walk, veering away from two officers who are emerging from a vehicle and drawing their guns.
Almost immediately, one of the officers appears to fire from close range. McDonald spins around and crumples to the pavement. The second officer simultaneously lowers his weapon.
The car with the camera continues to roll forward until the officers are out of the frame. Then McDonald can be seen lying on the ground, moving occasionally. At least two small puffs of smoke or dust are seen coming off his body as the officer continues firing.
In the final moments, an officer kicks something out of McDonald's hands.
Police have said the teen had a knife. Alvarez, Cook County State's Attorney, said Tuesday that a 3-inch knife with its blade folded into the handle was recovered from the scene.
For months, Chicago leaders had feared that the release of the video could provoke the kind of turmoil that rocked cities such as Baltimore and Ferguson, Missouri, after young black men were slain by police or died in police custody.
Twenty misconduct complaints were made against Van Dyke in the past four and a half years — but none led to disciplinary action from the Chicago Police Department, according to research by Craig Futterman, a University of Chicago law professor and expert on police accountability issues.
Complaints against police are not uncommon. But the number filed against Van Dyke was high compared with other officers. At least one person he arrested was later awarded $350,000 in damages in a lawsuit.
“The Chicago Police Department refuses to look at potential patterns of misconduct complaints when investigating police misconduct,” Futterman said. “If the department did look at these patterns when investigating police abuse, there is a great chance right now that 17-year-old boy would still be alive.”
He believes Van Dyke is the first Chicago police officer to be criminally charged for an on-duty shooting.
McDonald's death came at a time of intense national debate over police use of deadly force, especially against minorities. A number of U.S. cities have seen protests over police violence in the past 18 months, some of them fueled by video footage of the deaths.
The uproar was a factor in the rise of the Black Lives Matter civil rights movement, and has become an issue in the 2016 U.S. presidential election campaign.
Van Dyke's lawyer, Daniel Herbert, told CNN that the video was not an indicator of his client's guilt. He said Van Dyke arrived on a street on the southwest side of Chicago 18 minutes after a suspect carrying a knife was reported to have threatened businesses and vandalized police cruisers.
"Video by its nature is two dimensional. It distorts images. So what appears to be clear on a video sometimes is not always that clear," Herbert said. Van Dyke, he said, "truly was in fear for his life as well as the lives of his fellow police officers."
Also Wednesday, a Cook County judge dismissed a charge against a protester accused of hitting a police officer in the hours after the video was made public.
Judge Peggy Chiampas said the state's attorney's office recommended dropping the charge against 22-year-old Malcolm London and told London he was free to go.
London, who was wearing a T-shirt with the phrase "Unapologetically black" on it, walked outside the courthouse to loud cheers.
Prosecutors did not explain why they sought to dismiss the charge. London was among five people arrested on charges that included weapons possession and resisting arrest.
Al Jazeera and wire services