CHICAGO (WLS) -- A woman was critically wounded in a shooting on the Stevenson Expressway Thursday night involving an off-duty Chicago police officer, authorities said.
Illinois State Police said they are investigating the possibility of road rage between two vehicles.
The Civilian Office of Police Accountability said an off-duty Chicago police officer was involved in the shooting. Details on the officer's involvement have not been released.
State troopers responded to a reported shooting in the inbound lanes of I-55 near Archer Avenue at about 10:05 p.m.
A woman in her 20s was found shot inside a vehicle. Two other occupants inside the vehicle were not injured, Illinois State Police said.
The woman was transported to Northwestern Memorial Hospital in critical condition, police said.
Illinois State Police described the car the woman was in as the "offending" vehicle.
Police are investigating reports of another vehicle at the scene of the shooting but it's not clear if the person inside is involved or just a witness.
The Stevenson Expressway was shut down to traffic overnight but reopened early Friday morning.
Further details were not immediately available.