On the other hand, deceased Narayani Devi's eldest son Dinesh has submitted a complaint at the Burari police station to demand registration of a case against unidentified persons for what he called "killing his family".

"I was informed by a neighbour of my brother's family that my brothers, mother and other family members were found dead in their house in Delhi. I reached Delhi on Sunday night and suspect that someone killed them. They have not died in a ritual which went wrong," Dinesh said.

"Every Hindu family performs worship, havans and kirtans. Thus, my family also did it. What is unusual in it? It doesn't mean that some godman or occultists killed them. I had visited them 10 days ago. The entire family was happy as my sister Pratibha's daughter Priyanka had got engaged," he said.

The dead were meanwhile cremated at the Nigambodh Ghat here by family members and relatives amid heavy police deployment.

Joint Commissioner of Police Alok Kumar said initial post-mortem reports revealed that the bodies bore no marks of either strangulation or scuffle, indicating that it may either be a case of mass suicide or murder-suicide.

"A medical board of six doctors conducted the autopsies. It revealed that 10 family members died of hanging. Only Narayani Devi died due of strangulation. Further investigation is underway," Kumar said.

Another police officer, who did not want to be named, said the report firms up the police suspicion that the deaths were part of a suicide pact carried out as a religious practice.

The police is matching fingerprints of the deceased and suspects that someone from among the dead may have strangulated Narayani Devi before his or her hanging.

The autopsies also suggested that of the 11, six family members had dinner before their deaths.

Earlier, police said it had seized handwritten notes in the prayer area of the two-storey house in Sant Nagar in Burari, revealing a possible mystical connection to the deaths.

All but one of the bodies were found hanging from the ceiling and pipes. Most of them were blindfolded, gagged and their hands tied behind their back. As many as 11 pipes with different angles were found installed in a house wall.

The oldest, Narayan Devi, 77, was found on the floor with signs of strangulation.

The notes hinting at mysticism were found in a diary in the prayer area. The texts of pages discussed spirituality, salvation, rituals and few dates of last month. The notes were written on June 27 and 28 on the day of 'Vat Purnima'.

Articles used as offerings durign pratyers and rituals such as ghee, incense burner and grains were also recovered.

The police suspected an occultist or a godman behind the deaths.

The officer said that the notes had instructions like "everyone should be blindfolded properly, nothing but zenith should be visible to the eyes.

"When you all were hanging during that period, God will miraculously appear and save you all at the moment."

The police officer said almost every instruction in the note seemed to have been followed by the family for "obtaining salvation".

The deceased were Narayani Devi's sons Bhavnesh Bhatia, 50, and Lalit Bhatia, 45, and daughters Pratibha, 57, and Priyanka, 33.

Bhavnesh's wife Savita, 48, and their children Nitu, 25, Monu, 23, and Dhruv, 15, were also found dead along with Lalit's wife Tina, 42, and their son Shivam, 15.

The Bhatias ran a grocery stone and a plywood outlet in the neighbourhood.

Dinesh lives in Rajasthan's Kota while his another sister Sujata lives in Panipat in Haryana.