New Delhi, Jan 19 : Six persons, including four women, died when a fire broke out in a house in Delhi's Pitampura area on Thursday as they were unable to escape due to malfunctioning electronic door locks, sources said. The incident occurred on Thursday. The victims were identified as Rakesh Gupta, 62, his wife Renu Gupta, 62, Shweta, 30, Kirti, 25, Shanu Verma, 27, and Santosh, 25, all residents of a 4-storey building where the fire broke out on the first and second floors. Preliminary investigations point to a room heater on the first floor as the probable cause of the fire. It is believed that the heater, possibly used to dry wet clothes, sparked flames that quickly engulfed the duplex house. According to official sources, an elderly woman residing on the first floor had switched on the room heater before leaving the house to purchase medicines. In her absence, it is suspected that clothing near the heater ignited, leading to a rapid spread of the fire throughout the building. As occupants on the third and fourth floors attempted to escape by opening their windows, thick smoke filled the air, making it impossible for them to flee. The lack of a clear evacuation route compounded the disaster, as the residents were unable to use the staircase due to malfunctioning electronic door locks. The electronic doors, equipped with automatic locks, failed to open during the emergency, leaving the occupants trapped inside. Investigators revealed that the wires connecting the doors and the control box on the first floor were damaged in the fire, rendering the electronic locking mechanism useless. Emergency responders rushed to the spot, battling the blaze and attempting to rescue those trapped within. However, the intensity of the fire and the resulting smoke proved fatal for the six persons, who succumbed before help could reach them. "A case under section 285, 336 and 304 A of Indian Penal Code (IPC) has been registered at Maurya Enclave police station," a police official said. /IANS