Burari deaths explained: 11 bodies, a pet dog and a mysterious diary

The shocking incident of what appears to be a mass suicide by 11 members of a family in Delhi's Burari remains a deep mystery for the police despite enough proof that the family committed the act as an occult ritual to attain "mass salvation".
What happened?
Bodies of eleven members of the Bhatia family were found at a house in Delhi's Burari area early on Sunday morning. Ten bodies were found hanging and blindfolded, while another, the eldest family member Narayani Bhatia, 77, was found strangled in a separate room. The rest, including two 15-year-old boys, allegedly used chunnis (scarves) with religious motifs and cables to hang themselves. They were gagged and blindfolded, with hands tied. Cotton buds were found stuffed in their ears. The only one found alive in the house was the family dog, Jacky, who had been sent to the terrace.
Who were the Bhatias?
The Bhatia family ran a grocery shop and plywood business out of their double-storey home in Sant Nagar, in north Delhi's Burari's area. "Their shop would open by 6 am every morning but when it did not till 7.30 am today, a neighbour went to check and later informed the police after finding most of them hanging. The Bhatias lived on the first floor of house number 137/5/2 in lane number 2 of Sant Nagar. Narayani had two sons, Bhavnesh (50) and Lalit (45), who lived in the house with their respective wives, Savita (48) and Teena (42). Bhavnesh had three children Nitu (25), Monu (23) and Dhruv (15), while Lalit had a 15-year-old son, Shivam. Narayani’s elder daughter, Pratibha (57) also lived in the house with her daughter, Priyanka (33) after her husband died a few years ago. All of them were found dead.
What are the various theories?
Though no suicide note has been recovered yet, prima facie, the police suspects the Bhatia family committed suicide. But the police is also investigating the case with other possible angles of homicide. It is also checking the CCTV footage and not ruling out anything. This means it could also be a case of murders.