The boy was identified as Steven Rosenthal, according to the Cook County Medical Examiner's Office. His death was ruled a suicide.
Rosenthal, who friends said he loved basketball, was in the 1500-block of South Keeler Avenue in Chicago's Lawndale neighborhood when he was stopped by police.
He lived in the area with relatives since the death of both his parents. His mother died just two months ago, family said.
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Police said that Rosenthal appeared to have a gun. When the officers tried to question him, he ran. Officers pursued him on foot as he ran into an apartment building. Shortly after, officers said they heard a gunshot.
Rosenthal sustained a self-inflicted gunshot wound to the head. He was taken to Mt. Sinai Hospital in critical condition, where he died.
Bishop Terry Rogers, the family's pastor, tried Saturday to comfort the family and community. Rogers baptized Rosenthal when he was a baby and officiated over his mother's recent funeral.
"We were just healing and just getting over it and then this happens. We're devastated," Rogers said.
Friends and family said Rosenthal's death is more difficult because of the circumstances. They don't believe the medical examiner's suicide ruling.
One of the Rosenthal's aunts who asked not to be identified said she does not believe he shot himself.
"He was a baby. He had a life to live. Where's the evidence? We want to see the evidence," the aunt said.
Rosenthal's cousin said that when cops tried to question the teen he ran up the back stairs of his grandmother's home and tried to get inside.
"They thought he had a gun because he had his hoodie on. I heard a shot. I'm standing right here watching. I seen them shoot him," said cousin Keyshan Baines.