CHICAGO (CBS)– Police are investigating an armed carjacking in Calumet Heights.

Police said a 21-year-old woman was sitting in her car in the Trinity Hospital parking lot, just before 5 a.m., when four or five offenders exited a gray BMW and approached her vehicle. She said the offenders displayed a handgun, forcing her out of her car and onto the ground.

According to police, the woman tried to hang onto the door of her car, but let go once the offenders got into her car and drove away.

The offenders quickly struck a rail in front of the parking lot before fleeing the scene in both the victim’s car and the BMW.

The 21-year-old woman was treated at Trinity Hospital for a minor foot injury.

Police said the offenders may be teenagers.

No one is in custody and this incident is under investigation.