A 23-year-old journalism graduate Karishma Chauhan and her parents - Rekha and Yogendra Pratap - were found dead under mysterious circumstances at their residence in outer Delhi's Rohini Sector 17 on Friday morning.
The incident came to light at 7am when the priest of a local temple, who had organised a trip to Vaishno Devi, went to call Rekha who too was supposed to go on the pilgrimage.
Yogendra's body was found lying in a pool of blood on his bed on the ground floor of the two-storey residence.
The small-time businessman had injuries at the back of his head and near his left ear. Police said he had died of excessive bleeding.
Karishma and Rekha were found lying on the floor of the first-floor bedroom.
An injury mark on Karishma's forehead suggested she was also hit with a blunt object. She was strangled with a scarf, while Rekha was strangled with the cable of an electric iron. A case of murder has been registered.
Entry into the house was friendly, hence investigators believe the killers were known to the victims.