In a case of suspected mass suicide, eleven members of a joint family were found dead in India's capital New Delhi on Sunday with 10 of them hanging blindfolded with mouths tapped from an iron grill ceiling and one spotted strangled in another room.

Police found a diary at the residence that spoke about strange religious beliefs and also had detailed instructions about how hangings should be conducted, providing a motive to the case. Some of the notes were written a few months ago, police said.

"The human body is temporary and one can overcome fear by covering their eyes and mouth," one of the notes in the diary read.

"The notes say if a group of 11 people follows these rituals, all problems would ease out and they would attain salvation. Some notes have dates on which they were written while others didn't have it. All the notes talk about reaching the end and gaining peace," one of the officers investigating the incident said, local channel NDTV reported.

Joint Commissioner of Police (Crime) Alok Kumar said they found handwritten notes detailing how hands and legs are to be tied, that are quite similar to the manner in which the bodies were found. Police are now looking into the family’s links with occult practitioners.

The bodies were first discovered by one of the neighbors Sunday morning. He alerted the police after he saw the bodies of four men and six women in the courtyard of the two-story house which included three teenagers. The family dog was found alive in the terrace.

"Their shop would open by 6 a.m. (8.30 p.m. EDT) every morning but when it did not till 7.30 a.m. today, a neighbor went to buy milk. Upon checking, the neighbor found the main door of their residence open, prompting him to inform the police," Joint Commissioner of Police Rajesh Khurana said.

"Prima facie, we suspect they committed suicide but we are also investigating the case with other possible angles of homicide. We are not ruling out anything. We are also checking the CCTV footages." he added, The News Minute reported.

The family ran a grocery shop and plywood business and did not have financial issues.

“They were not facing any financial issues and had not taken even a single loan. Everything was fine. Why would they kill themselves?" said Ketan Nagpal, whose maternal grandmother was one of the people found dead.

Neighbors said the family was very religious and would chant religious hymns every day but there was nothing suspicious about it.

"They would chant 'Gayatri Mantra' and worship the gods once during morning and once in the evening. We never saw any 'tantrik' or godman visiting their house. They were helpful and humble," one of the neighbors said.

Police are awaiting the autopsy report which would make it clear if it was a suicide pact or if one of the family members killed others and then committed suicide.

"It is a tragic incident. I have spoken to the police. Let's wait for their investigation to be over," Chief Minister of Delhi, Arvind Kejriwal, said.