The four were found dead in their house in Sadiq Nagar on March 1. While R&AW officer Annanya Chakrabortys body was found hanging, his wife Jayshree, son Arnab, and daughter Disha, were found lying in a pool of blood.
Police said Annanya had killed his family before committing suicide.
According to police, initial findings of Jayshrees autopsy show that she was attacked on the face and head more than 14 times.
It was found that the attack on Jayshree was far more brutal than the one on Arnab, who sustained seven injuries, or on Disha, who had eight injuries on her face and head.
Jayshrees case was that of excessive killing, wherein, one injury is fatal enough to cause death but the murderer still inflicts a series of such injuries out of hatred, to make sure that the person is dead. This was one such case. A medical board of four members was constituted to conduct the post-mortem examination, which was also videographed, a source said.
Meanwhile, police, who have questioned Annanyas friends and relatives, have found that he had a problem with his wife working as a teacher in a private school. Police said the couple used to fight frequently over the issue.
According to the neighbours accounts, the couple was heard fighting over the matter just a few days before the incident. During the fight, neighbours claimed, Annanya had abused his wife.
Speaking to Newsline, one of Dishas friends, who is a student of class VII, said Disha often complained about her father ill-treating her. The friend said Disha was very upset because of the fights at home and also told her that Annanya and Jayshree were looking at a divorce. She told me that her parents were getting separated because of frequent fights at home. She used to tell me about her fathers short temper and that she was scared of him, the friend said.
Teachers at Kendriya Vidyalaya, Sadiq Nagar, where both Disha and Arnab studied, told Newsline that both the children were brilliant students and never complained of problems at home.
The teachers said even though Annanya never turned up for the parent-teacher meetings in school, their mother attended them regularly.
Police have also found that Annanya was insecure about his children being closer to their mother.
Police said they were awaiting the final post-mortem report.
They still have not been able to identify the reason that triggered the entire episode.
We have figured out a host of things after questioning the family and friends of the Chakrabortys. We are now trying to string them together to figure out what triggered the incident. It is, however, clear that Annanya first killed his daughter, son and wife before committing suicide, an officer said.