A man shot and wounded a teenage boy who he said showed a gun after breaking into his car in the West Chesterfield neighborhood on Chicago's South Side.

Police said at 3:42 a.m., a 58-year-old man heard his car alarm going off in the 9400 block of South Indiana Avenue. He went outside and found the driver's side window broken, and two males inside his parked car who had no business there, police said.

The man said one of the people in his car took out a gun. At that point, the man, who had a valid Firearm Owners Identification Card and Concealed Carry License, took out his own gun and fired shots, police said.

A 17-year-old boy who had been in the car was shot in the right forearm and the left knee and was taken to the University of Chicago Medical Center in fair condition, police said.

The second suspect fled east on foot before getting into a gray minivan.

No other injuries were reported.

Calumet Area detectives are investigating.