Chicago was bracing for protests as the footage of the March 29 shooting was released.
Chicago recorded a total of 240 shooting victims in January, both fatal and non-fatal combined, with 51 of those being classified as homicides.
Ashton Lipscomb, 9, was found by police motionless and bleeding from a head wound.
The city had 550 more shooting victims this year compared with the same period, January 1 through July 11, in 2019.
The mayor said that those who violate "very clear directives of the Chicago Police Department" will be fired.
Mayor Lori Lightfoot responded to protests over the death of George Floyd by calling for a citywide moment of silence Sunday evening and declaring, "we will be able to learn from this moment."
Chicago recorded its most violent Memorial Day weekend in years, with nine dead and at least 36 others injured with more than 24 hours left in the unofficial start to summer 2020.
The coronavirus pandemic has not slowed shootings in the greater Chicago area, with 498 shooting victims recorded in the city through March 31—and an additional 20 people shot in the first weekend of April alone.
There were 492 homicides in Chicago in 2019, down 13 percent from the previous year and down 38 percent from 2016, according to official statistics.
"This really does shine a light -- not only on the case in of itself, but it shines a light on how mismanaged the office is. There really are serious cases being mismanaged."
Coles was three months pregnant at the time of her disappearance on Tuesday, October 2.
As Chicago police officer Jason Van Dyke awaited his fate, threats against the cop and his kin were still being investigated and city schools were bracing for potential civil unrest.
The twin daughters and pastor of Bettie Jones are calling for justice after new report finds shooting "not justified."
A drug investigation-turned-shootout left a suspect dead and three cops injured in Chicago's West Side on Monday.
The mayor called for "the complete and total reform of the system and policing culture."
Quintonio LeGrier and Bettie Jones were shot and killed the day after Christmas.
Quintonio Legrier, a 19-year-old black student, was also killed.
The demonstrators chanted, "Sixteen shots and a cover-up!" and "Rahm, resign!"
A Chicago police officer last month was charged with first-degree murder.