Nearly 30 pieces of video and other materials were posted to the COPA website just after 2:30 p.m. Thursday.
The material includes 17 bodycam videos from involved and responding police officers, four third-party videos, one OEMC transmission, two audio recordings of 911 calls, six ShotSpotter recordings, and case and response reports.
Warning: The following video may be disturbing or upsetting
The shooting occurred at about 3 a.m. on March 29. 10th District Officer Eric Stillman and his partner just arrived, handling a call for shots fired.
They took a 21-year-old man into custody and said the other subject-Adam Toledo, took off running.
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Stillman's body-worn camera recorded the brief and fast foot chase into the alley and then the critical moment, frozen in time.
Stillman reported seeing a gun in Toledo's right hand. Although it is difficult to see, police said the gun is visible in one frame in Toledo's right hand, down at his side. Some experts told the ABC7 I-Team the slide is out because the magazine was emptied. That gun ended up a few feet away.
What happened next, in a fraction of a second, cost Toledo his life. His hands moved upward, and Officer Stillman fired one, fatal shot into the teenager's chest.
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Authorities have also released video from Officer Stillman's body worn camera of a gun a few feet away behind a fence Toledo was standing next to, as if he tossed it aside when Stillman had him cornered. Police said Toledo was shot as this played out in about one second.
Stillman immediately called for medical assistance after the shooting and also immediately rendered aid to Toledo after the shooting, which can also be seen on his bodycam video.
Another video released shows the shooting from the angle of surveillance camera with a wider view of the alley where it occurred. Toledo can be seen in a gap in the fencing.
The police report says Stillman said Toledo did not follow verbal directions, fled, used significant force and was armed with a semiautomatic pistol.
"This incident was solved in .8 milliseconds, so it happened very quickly, it happened probably faster than science had proved an officer would be able to think his way through the situation," said Ed Farrell, former U.S. Marshals Service supervisory inspector.
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ABC7 Legal Analyst Gil Soffer, a former federal prosecutor, said the case comes down to a question of when Toledo was shot.
"Within a second before that, we see what appears to be a gun in Toledo's hand and that he drops it before he raises his hands," Soffer explained. "If that's the case, the officer has a very credible defense.
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But not all experts see the split second decision captured in this picture the same way.
"It appears to me that the young man had his hands up when he was shot," said attorney Tony Thedford of Thedford Garber Law. "It appears to me that when the young man made the move to the gate or the fence, that opening where the shooting occurred, before he turned around it appears if he had a gun he disposed of it right before the shooting. It's very evident to me that he did not have the gun at the time the officer fired his weapon."
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"You see Mr. Toledo raise his hands and turn around," said attorney Anthony Burch. "If you look at that and listen to what is going on, he is following the directions of the police officer and he's shot."
In a statement to ABC News, Tim Grace, the attorney for CPD Officer Eric Stillman said Adam Toledo "had the gun in his right hand, came to a fence, looked at the officer, which could be interpreted as attempting to acquire a target."
"At this point the officer was faced with a life threatening and deadly force situation. All prior attempts to deescalate and gain compliance with all of the officers lawful orders had failed. The officer had no place to take cover or concealment, the gun was being orientate in his direction and he was left with no other option," Grace said.
"A police officer is trained and it is ingrained in them from the moment they enter the Chicago Police Academy that deadly force is a last resort and is only justified when the officer is confronted with an imminent threat of death or great bodily harm to himself or herself or another person. They do not take this lightly. They have no duty to retreat, they have a duty to stop the threat and save lives," the statement continued.
During a Chicago Police Board meeting Thursday night, Chicago Police Superintendent David Brown shared a message for the Toledo family.
"I want to convey my deepest condolences to the Toledo family and my appreciation for the family's call for calm and for peace during this difficult time," Superintendent Brown said.
The superintendent said COPA has his department's full cooperation.
John Catanzara, the head of Chicago's police union, defended the officer's decision to shoot Toledo in an interview on CNN.
"It is 100% justified," he said. "That officer's actions were actually heroic. There's a very good reason why he only shot once. Like I said, he could have been shot multiple times, but the officer assessed in a split second. Unfortunately, he committed to the first shot already, justifiably so."
Catanzara said anyone would have feared for their life in that situation.
Chicago police said Toledo was fatally shot as he and 21-year-old Ruben Roman ran from police down an alley in Little Village about 2:30 a.m. March 29.
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ShotSpotter video released by COPA supports the narrative prosecutors gave in court. It records six to eight gunshots, which along with 911 calls prompted police to respond to the area.
At the scene, police arrested Roman who is believed to be the other person in the alley seen on the bodycam video. He remains locked up on gun and child endangerment charges related to the shooting.
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In court Saturday, prosecutors said surveillance video captured the moments Roman fired shots at a passing vehicle with Toledo at his side.
Prosecutors detailed what they say plays out in the police video, explaining it reportedly shows Toledo stopped after a foot chase with his left side facing the officer.
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Prosecutors described Toledo as having a gun in his right hand, and say when he turned towards the officer, the officer shot him in the chest.
Prosecutors said a handgun fell from Toledo's hand. Thursday afternoon the Cook County State's Attorney's Office released a statement about that claim, saying, "An attorney who works in this office failed to fully inform himself before speaking in court. Errors like that cannot happen and this has been addressed with the individual involved. The video speaks for itself."
Police said the gun found at the scene was previously used by Roman and matched the shell casings found at the site. Police believe Roman fired the shots picked up by the ShotSpotter and then gave Toledo the gun.
Even with the release of these videos by COPA, the civilian agency investigators will now examine the timing of how this played out, what the threat was to the officer in the moment, and whether he followed department pursuit and deadly force rules.
COPA will review witness accounts, reports by Stillman and others, and question officers who were present to determine whether the use of force in this case was justified. That process will take some time.
The video was viewed by Toledo's family Tuesday evening. In a written statement, attorneys for the Toledo family expressed gratitude for the opportunity to review the video before its public release, calling the experience "extremely difficult and heartbreaking for everyone present, especially Adam's family."
Toledo family attorney says Adam complied before shooting
The Toledo family attorney spoke following the video release, saying she wants the bodycam video forensically analyzed and emphasizing that Toledo did not have a gun in his hand when he was shot and was complying with police orders.
"I'm not going to deny that, that it could have been a gun. But I can't tell you with 100% certainty until I have that video forensically analyzed and enhanced," said Adeena Weiss Ortiz, attorney. "But it's not relevant, because he tossed the gun. If he had a gun, he tossed it. The officer said 'show me your hands,' he complied, he turned around."
WATCH: Full statement from Toledo family attorney Adeena Weiss Ortiz
"At the time Adam was shot he did not have a gun, OK? In that slow-mo version, whatever he had in his hand whether it was a gun or something else, there was something in his hand, he approaches the fence, he lets it go, he turns around and he's shot," she added.
Ortiz called for calm in the wake of the newly-released video. She said she wants justice for Adam and peace in the wake of the incident, and thanked the Little Village community for its support on behalf f the family, and at this point has not indicated whether a lawsuit will be filed.
His mother Elizabeth Toledo again asked for privacy. Attorneys for the Toledo family released the following statement Friday: "We understand that emotions in the community are running high in the wake of the release of police body camera and other videos depicting the March 29 police shooting of 13-year-old Adam Toledo and that protests are planned for later today. The Toledo family implores everyone who gathers in Adam's name to remain peaceful, respectful and nonviolent and to continue to work constructively and tirelessly for reform. The family is forever grateful to the leaders and members of Chicago's Latino community and the residents of Little Village for their support in this time of grief and mourning."