Chicago police have released graphic footage of an officer shooting dead a 13-year-old boy in a dark alley.
Police say what was in Toledo's hand is a gun that was later recovered from behind the fence where the chase ended.
Bodycam video shows the policeman shouting "drop it" before shooting Adam Toledo once in the chest on 29 March.
The boy does not appear to be holding a weapon in the split second he is shot, but police video shows a handgun near the spot where he falls.
Small protests were held on Thursday evening around Chicago, hours after the city's mayor appealed for calm.
The video's release follows the fatal police shooting on 11 April of Daunte Wright by an officer in a Minneapolis suburb.
That shooting has sparked violent protests as the city awaits the outcome of the trial of Derek Chauvin, the officer accused in the death of George Floyd.
Prosecutors, in charging a 21-year-old man who was with Toledo at the beginning of the police encounter in the early morning hours of March 29, said the gun recovered a few feet from the boy's body matched shell casings located where police were summoned moments earlier, and that Toledo's hand and gloves dropped by the older man had tested positive for gunshot residue.
Body-worn camera videos were released by Chicago's Civilian Office of Police Accountability (COPA) , the police oversight agency that reviews incidents in which an officer fires a department issued handgun. Documents released by COPA identify the officer who fired his weapon as 34-year-old Eric Stillman.
Chicago's mayor, Lori Lightfoot, released a joint statement with Toledo's family and held a press conference Thursday afternoon calling the video "difficult to watch."
"Simply put, we failed Adam," she said. "And we cannot afford to fail one more young person in our city."
"We live in a city that is traumatised by a long history of police violence and misconduct," the mayor said. "So while we don't have enough information to be the judge and jury of this particular situation, it is certainly understandable why so many of our residents are feeling that all too familiar surge of outrage and pain."
The Chicago Police Department would not answer questions about the shooting but released a slowed-down video that highlights a portion of the interaction between the officer and Toledo.
Timothy Grace, a union lawyer representing Stillman, said the case was tragic but his client was placed in a situation where he was "left with no other option."
"The juvenile had a handgun in his right hand, given verbal direction, told to drop and stop and to adhere to the police officer's valid, lawful orders and the juvenile begins to turn," he said. "At that point (the officer) has no cover, no concealment, he's left with no other option."
"He feels horrible about the outcome. He feels horrible he had to use deadly force. No police officer wants to use deadly force in the line of duty. He was well within his justification of using deadly force, he just feels horrible."
Mr Stillman, a military veteran, joined the force in 2015. He has had four use of force reports and three complaints filed against him, according to the Invisible Institute, which publishes data about police misconduct in Chicago.
Police in the area were alerted to the sound of gunfire that was picked up by the ShotSpotter technology the city uses to alert officers to gunfire almost instantly, often a minute or more before 911 calls are able to be broadcast over the police radio.
Officers responding to the area were told eight shots had been fired, according to police radio traffic released by authorities. The entire encounter between the officer picks up less than two minutes into the video and lasts less than 20 seconds, after the officer who shot Toledo opens the door to his police cruiser and starts chasing the 13-year-old and 21-year-old, identified by authorities as Ruben Roman.
The policeman shouts: "Police! Stop! Stop right [expletive] now! Hands! Hands! Show me your [expletive] hands!"
The boy turns and raises his hands. The officer shouts "Drop it" and fires his weapon - 19 seconds after exiting his squad car.
Separate CCTV footage appears to show the teenager throwing something through a gap in the fence as the officer runs up to him. Bodycam video shows officers shining a light on a handgun behind the wooden fence after the shooting.
The policeman calls for an ambulance while urging the fallen boy to "stay awake". Other officers arrive at the scene in the Little Village neighbourhood on the city's west side and CPR is performed.
Mr Roman appeared in court on Saturday charged with aggravated unlawful use of a weapon, reckless discharge of a firearm and child endangerment, according to local media reports.
The Toledo family attorney said the family is currently exploring next steps and did not rule out potential legal action against the officer or the City of Chicago.