The city's use of force policy explicitly bars police from shooting into a car when the vehicle represents the only danger.
The videos are laden with profanity.
"I think I shot that motherf---er,man,"one officer can be heard saying. He tells other officers the person he shot is three houses over.
Sharon Fairley,chief administrator of IPRA,said in a statement that the agency is proceeding"as deliberately and expediently as possible in pursuit of a swift but fair determination"into the teenager's shooting.
Ms Fairley said the footage"as shocking and disturbing as it is,is not the only evidence to be gathered and analysed when conducting a fair and thorough assessment of (the) conduct of police officers in performing their duties."
Police Superintendent Eddie Johnson took quick action after the shooting,stripping three officers of their police powers and saying it appeared they had violated departmental policies.
Mr O'Neal's family is suing the department.
Chicago police officers tried to stop Mr O'Neal about 7.30pm on July 28 in the South Shore neighbourhood as he drove a Jaguar convertible reported stolen in suburban Bolingbrook,police said.
Surveillance cameras tied Mr O'Neal and three others to a spree of car thefts,officials in the suburb said.
Mr O'Neal struck two Chicago police vehicles in the sports car,and two officers fired at him while he was in the car,authorities said. He then fled from the car,police said,and a third officer chased him behind a home. After Mr O'Neal refused to stop,the officer shot him.
Mr O'Neal,who was unarmed,died of a gunshot wound to the back,authorities said.
The shooting itself was not captured on video,department officials said,even though the officer who chased and shot Mr O'Neal was wearing a body camera.
Mayor Rahm Emanuel has pointed to body cameras as a tool to build trust in the police;department officials have not said why the camera did not record the shooting.
The city's quick moves after Mr O'Neal's shooting show how much has changed in the eight months since the release of video of a white police officer shooting black 17-year-old Laquan McDonald 16 times. The officer who shot Mr McDonald,Jason Van Dyke,is charged with murder.
The McDonald video – and long-simmering dissatisfaction with police use of force among many African-Americans – led to sustained protests,and the US Justice Department launched an investigation to determine whether police had systematically violated residents'rights.
Shootings involving police officers atBaton Rouge,Dallas,Miami and elsewhere have stoked public anger about police treatment of African-Americans.
Federally enforced changes could come from that ongoing investigation,and Mr Emanuel has announced or enacted a raft of reforms to policing and officer oversight.
Police Superintendent Johnson broke with tradition by saying police appeared to have violated departmental policy in the O'Neal case. The superintendent,who was appointed by Emanuel amid the political crisis sparked by the McDonald video,issued an unusual department-wide memo saying that the information he had on the shooting"left (him) with more questions than answers."
The case also represents an about-face for city officials who have previously fought to prevent the release of videos of police shootings for as long as possible.
In February,Mr Emanuel announced the city would start releasing videos of shootings and other major uses of force within two to three months. Friday's release came just eight days after the shooting.
The three officers are stripped of police authority pending an internal investigation and an inquiry by IPRA,which is also in transition. As detailed in a recent Tribune investigation,IPRA has long conducted superficial investigations and recommended light punishments.
Mr Emanuel has announced plans to abolish the agency and replace it with a more effective department,though neither he nor his allies have announced any details. Meanwhile,IPRA's leader,former federal prosecutor Ms Fairley,has sought to reform the department even as it faces its demise.
Under Fairley,who was appointed in the wake of the McDonald video's release,IPRA has ruled more police shootings unjustified in the past two months than it had in the prior nine years.
Two of the shootings IPRA recently ruled unjustified involved officers shooting at vehicles,as they appear to have done in Mr O'Neal's case. In both of the shootings ruled unjustified,IPRA determined the officers faced no serious danger when they fired.
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The department revised its deadly force rules in February 2015 to ban firing into a vehicle when the automobile is the only force used against an officer or bystander.
McClatchy