The attack occurred late Monday in an area police describe as a "hotbed" of narcotics transactions. A 19-year-old man got out of a vehicle and tried to shoot a 23-year-old man on the sidewalk, but the weapon malfunctioned. During a struggle for the gun, it discharged and the bullet nicked the intended victim in the shoulder, police said.
The alleged gunman began running away, but witnesses chased him and stomped on his head, the Chicago Tribune reported Tuesday.
The man shot was released from a hospital, and police said he told them he didn't want to press charges.
The alleged gunman suffered major head trauma and was in critical condition at John H. Stroger, Jr. Hospital of Cook County in Chicago, where he was breathing with the assistance of a machine, police said.
No names were released.