Chicago police say they won't charge a customer with a concealed carry license who shot and killed an armed man who was attempting to rob a store.

Department spokesman Anthony Guglielmi says investigators classified the shooting as self-defense after they reviewed witness statements and surveillance videos from the store and currency exchange.

The shooting occurred at 7 p.m. Saturday on Chicago's southwest side. Police say a masked man later identified as 55-year-old Reginald Gildersleeve displayed a handgun and announced a robbery of an employee.

The customer fatally shot Gildersleeve sometime after the robber pointed his weapon at another employee and forced her to the back of the store.

Police have not identified the customer.

Scott Olson, Getty Images