CHICAGO (AP) — Chicago's police superintendent says an off-duty officer was in his personal vehicle when he saw a suspicious-looking man, starting a confrontation during which the officer shot the man in the arm.

Police said the shooting injuring an 18-year-old man happened about 5 a.m. Sunday in the Morgan Park neighborhood on the city's far south side.

Superintendent Eddie Johnson says the man was released from a hospital after being treated for his wound. Johnson said Sunday the officer was a sergeant returning from work when he began to question the man.

Johnson says the encounter escalated as the man became "elusive and unresponsive." He said no weapon was immediately recovered at the scene and many unanswered questions remained under investigation.