Police said the shooting happened during an altercation and the man shot by police is hospitalized in serious condition.
Police chased him into an apartment building in the East Chatham neighborhood. At ground 7 p.m. Wednesday, police said they saw an armed man in a crowd of people near 79th Street and Drexel Avenue, so police chased after him when he ran away.
A group of about three officers followed the man into the third floor of an apartment building nearby, where they struggled according to authorities.
One officer fired one shot. The man did not return fire.
The events unfolded as children went door-to-door trick-or-treating with their parents.
"He ran into the building to third floor where he pushed his way in," said Chicago Police Patrol Chief Fred Waller. "Officers followed behind him. A struggle, a brief struggle, ensued there. He continued to run out of that building and that's when he was shot."
Waller said the man was shot inside the building and outside the apartment.
"Children have been walking down this street all day and all evening trick-or-treating," said Tou're Simpson, who lives nearby. "It's just too bad. It's a shame. Really it is."
Officers recovered a 9 millimeter weapon with an extended clip, releasing a picture of it.
Officers confront a group of individuals and observe an armed subject. They approach and offender run into a building where a confrontation ensues with police. The below weapon is recovered. Media briefing at 79th/Drexel momentarily by Chief of Patrol Fred Waller. pic.twitter.com/7ecdvtDrsI— Anthony Guglielmi (@AJGuglielmi) November 1, 2018
Family members told the Chicago Tribune that the man who was shot is 23 years old and is the father of two young children, a baby and a 2-year-old.
They are questioning if the use of force was justified.
Meanwhile, the officer has been put on administrative duty for 30 days, pending the outcome of an independent investigation.