The boy, identified by the Cook County medical examiner as Adam Toledo, lived near where the shooting happened in the Little Village neighborhood.
The initial police department statement said an officer shot him during an “armed confrontation” and tweeted a photo of a gun that a spokesperson said was recovered at the scene.
In a follow-up statement Thursday, Chicago Police Superintendent David Brown released a statement identifying the person shot by police as a juvenile but did not mention the boy’s age and declined to release his name.
Authorities have made no statements and answered no questions about the incident, including whether the officer was wearing a body camera, in the four days since.
The boy’s mother, Elizabeth Toledo, told CNN affiliate WLS in an interview, “I just want justice. I just want answers. What happened?”
The family released a statement, saying that although Toledo was killed Monday, his family was not notified for two days, CNN affiliate WLS reported.
The family said the boy was in seventh grade at Garvey School, and that he enjoyed sports.
Chicago Mayor Lori Lightfoot released a statement after the local media had reported the boy’s age.
According to police, officers were responding to a call about shots fired about 2:30 a.m. when they saw “two males in a nearby alley.” One of them was armed, according to police, and fled from the officers. One officer fired shots, hitting one person in the chest.
Police only said the boy “was pronounced deceased on scene” and didn’t specify the age of the person that the officer had shot.
The Civilian Office of Police Accountability, which investigates uses-of-force incidents by Chicago police, is reviewing the shooting and released a statement after the boy’s age became public. According to the agency, the officer was wearing a camera and fired one shot.
The mayor and police superintendent have called for release of the body camera footage.
“While the investigation is ongoing, it is critically important that COPA release relevant videos first to the family, and then to the public, as quickly as possible, with appropriate protections, given his age,” the mayor continued.
Investigative materials from police shooting investigations are typically released in 60 days, but according to the agency, the boy’s age prevents them from releasing video of the incident without a judicial order.
CNN’s Peter Nickeas contributed to this story.