A 35-year-old man identified as Hasnil Warekar murdered 14 members of his family, including his parents and 7 small children, in the early hours on Sunday, February 28, before taking his own life.
According to the police, the incident took place after the family members came together around 1 a.m. in his home at Kasarvadavil in Thane district, 32 kilometres from Mumbai.
"The attacker, Hasnin Anwar Warekar killed himself after slitting the throats of all other family members including his parents," a Thane police spokesman, Gajanan Laxman Kabdule, said"
The only surviving member of the family was Warekar's sister Subiya Bharmal, who was attacked with a knife. She escaped the attack and has been admitted to a nearby hospital.
"We still haven't been able to speak with the attacker's sister who is in deep trauma at a city hospital," Mr Kabule added.
Local media reports that Warekar attacked his family after reportedly lacing their food with sedatives. Indian Express newspaper said the man stabbed his victims after they went to bed, having all decided to spend the night at the house
"Prima facie evidence suggests that the accused bolted all the doors of the house and murdered his family while they were asleep with a knife that we found near his body," Ashutosh Dumbre, joint commissioner of Than police, said.
The police have sent the bodies for post-mortem examination. They have also sent food samples from the house for forensic analysis to determine if the food was mixed with any drug.
According to the Press Trust of India news agency, a property dispute was behind the multiple murders, but Mr Dumbre said initial investigations had so far found no trigger for such an extreme step.
"He worked as an accountant with a private company in Mumbai. There were no known troubles or disputes and now we are hoping that the lon survivor can tell us something about the trigger."