CHICAGO - A white Chicago policeman caught on tape shooting dead a black teenager had at least 20 complaints filed against him but was never disciplined, a database shows, in the latest such incident to inflame racial sentiment in the US.
The graphic video released shortly after officer Jason Van Dyke was charged with first-degree murder Tuesday has also reignited impassioned debate about the use of force by law enforcement in the United States, with Chicago left dangerously on edge.
Protesters there have likened the Laquan McDonald killing to that of Michael Brown, the black teenager shot dead by a white policeman in Ferguson, Missouri last year, triggering 15 months of demonstrations in major US cities over perceived police brutality against black men.
Chicago police initially said that McDonald was high on the hallucinogen PCP, acting erratically and lunged at officers with a knife when he was shot 16 times in October 2014.
But the dashcam video showed the 17-year-old walking away when Van Dyke opened fire and made no threatening gestures to justify the use of deadly force, prosecutors said in announcing the charges.
It was the first time a Chicago police officer has been charged with first-degree murder for an on-duty fatality in more than 30 years, the Chicago Tribune reported.
Prosecutors and city officials have come under intense criticism for trying to block the release of the video and taking so long to press charges against Van Dyke.
The case has been particularly painful for Edward Nance, who won a $350,000 civil judgment for injuries sustained when he was arrested by Van Dyke and his partner in 2007.
"It rocked him to the core," Nance's attorney, Michael McCready, told the Chicago Sun-Times.
"He said if they had done something about this cop in our case, this young boy would still be alive." Van Dyke was a member of the city's controversial and now-disbanded Tactical Response Unit which patrolled high-crime areas when he pulled Nance over because his car didn't have a front license plate.
Nance - who worked at a cable company and as a high-school sports referee - told investigators that Van Dyke's partner slammed his head on the hood of his car and that van Dyke violently handcuffed him and tossed him into a squad car.
The Independent Police Review Board dismissed the complaint because there were "no independent witnesses" and "no way to determine" the cause of Nance's injuries, the Sun-Times reported.
Seven other complaints against Van Dyke alleged excessive use of force and two involved the use of a firearm, the paper said.
The 20 citizen complaints filed against Van Dyke since 2011 is below the average allegation rate, according to the Citizen Police Data Project from the University of Chicago.
However, he is still among the "small subset" of officers responsible for a "disproportionate" number of complaints.
Prosecutors said Van Dyke, who joined the Chicago police in 2001, opened fire just 30 seconds after his vehicle pulled up to the scene and six seconds after stepping out of it.
Shot from an approaching police vehicle, the dashcam video shows McDonald run down the middle of the street towards another cruiser, hitch up his pants and then start to walk away from Van Dyke and his partner.
His body then spins and strikes the pavement. McDonald lifts his head, moves an arm and then a cloud from another gunshot rises up from his chest as he lies in a fetal position.
He does not move as an officer enters the frame for just long enough to kick a knife away from his prone hand.
None of the officers approaching McDonald to try to help him as he bleeds out on the street, writhing once in the remaining minute of video.