A 50-year-old security guard sustained gunshot injuries after unidentified persons allegedly opened fire at a cash van in an attempt to rob it near DND toll plaza in east Delhi's Mayur Vihar, police said Tuesday.\u00a0 The incident took place Monday night, they said. The cash van belonged to a security agency and three persons, including the security guard, driver and a custodian of the firm, were inside the vehicle during the time of the incident, police said. The injured security guard, identified as Vishambhar, was admitted to a nearby hospital, they said. Three to four men allegedly opened fire at the cash van which was enroute its Noida office after collecting cash from its office in Janakpuri, a senior police official said. The accused fled from the spot, leaving behind a car after their attempt to loot failed, he said. A vehicle, suspected to be that of the accused, has been taken into police custody, the official added. Police is scanning through the CCTV footage of the incident to trace the accused and to ascertain the sequence of the incident, the officer said.\u00a0 A case was registered, police said, adding that multiple teams have been formed to trace the accused.