Two females were shot Sunday afternoon in the 9900 block of Vincennes, police said.
The shooting occured at about 3:20 p.m., said Chicago Police News Affairs Officer John Mirabelli.
The Chicago Tribune reports that a 13-year-old girl and a 44-year-old woman were inside of their car at a gas station when they were shot.
An off-duty officer responded to the shooting and exchanged gun fire with a man on the 9800 block of Throop Street, Mirabelli said. The officer ordered the man to stop and he turned and began firing. That is when the off-duty officer began firing, Mirabelli said.
Neither the officer or the suspect was hit, although the officer's vehicle was struck several times, Mirabelli said.
The two victims were taken to Advocate Christ medical center in critical condition.
The suspect who exchanged fire with the officer is in custody and police are still searching for additional suspects and witnesses, Mirabelli said. Officers are working to determine exactly what happened.
Updated, 11:30 p.m.