The victims are Mohammad Ali, 60, and Tayeb Ali, 40, both hailed from Purbapara of Harbang bus station area.

Police said up to 15 criminals stormed into the market on Chittagong-Cox's Bazar highway at about 3:00am. They confined Ali and Tayeb at gunpoint and killed them on the spot.

The criminals broke into an adjacent grocery shop and beat up shopkeepers Samir and Sri Monta. They also critically injured another night guard and left the market at dawn.

Failed to commit robbery, the criminals killed the night guards, police suspect.

The injured are receiving treatment at Chittagong Medical College Hospital and the bodies of the night guards were sent to Cox's Bazar General Hospital for autopsy.