By Derrick Perkins (File Photo)

The three masked men who held up the Safeway supermarket in south Old Town at gunpoint on Sunday evening remain at large, police say.

The trio entered the store about 8:30 p.m. and demanded cash from a store clerk, who cooperated with the robbers. One person was injured during the heist, grazed by a bullet fired by one of the masked men, said police spokeswoman Ashley Hildebrandt. Emergency responders took the victim to a nearby hospital with minor wounds.

Hildebrandt did not know whether the individual, who has since been released from the hospital, was a store employee or a shopper. Several other customers and employees fled from the rear of the supermarket during the robbery.

Though local law enforcement received help from the U.S. Parks Police, which lent a helicopter to the overnight search effort, the trio escaped on foot. Officials did not say how much money the three grabbed during the heist.

Authorities urge anyone with information about the robbery to contact the police department’s criminal investigation section at 703-746-6711.