A software engineer along with his wife and son suffocated to death at their home in New Delhi on Wednesday, police said, adding the "room heater was found switched on".
Satish Kumar, 35, his wife Shashi, 30, and their five-month-old son Archit were found dead on the bed when the door of their rented home in south Delhi's Kotla Mubarakpur was broken open, said a police official.
The police responded around 8.30 am after getting a call.
"The caller informed Police Control Room that the victims were not opening the door despite repeated knocking," said the official.
"A room heater was found switched on inside the room which indicates that the victims died of suffocation," the official added.
Kumar, who belonged to Bihar, worked as a software engineer in a private company in Gurgaon, Haryana.