Shortly before midnight Wednesday, a man walked into a Subway restaurant located at 7470 Cherry Avenue, brandished a handgun at the clerk and demanded money, according to a police news release.
The employee complied with the robber's demands and handed over an undisclosed amount of cash, officials said.
The unidentified man ran out and fled possibly in a dark-colored truck with tinted windows.
The robber is described as appearing 18 to 25 years of age, standing about 6 feet tall wearing a light-colored jacket and dark pants.
Anyone with information on this case is asked to contact the Fontana station at 909-350-7700.