At least a dozen relatives and friends of the De family had partied at the 3 Robinson Street house last month in a room next to the one where a dead body and two dog corpses had been lying for months.

They did not get a whiff of the macabre, but left in a hurry after the host lost his rag on being asked where his sister and two dogs were.

To celebrate his birthday, Partha De, 44, had invited the family of his uncle, living in the same building complex, and a few friends to their house in the afternoon of May 10.

Things turned ugly after at least three of the guests, including his uncle Arun, began asking Partha about the whereabouts of his elder sister, Debjani, 46, and their two pet Labradors.

"He began shouting at us and asked us to leave the house immediately. He has a strange habit of shouting 'get out' whenever he loses his cool. But this time it was extremely insulting and we all left the house immediately," said Mukti De, Partha's aunt.

According to Mukti, this was the first time she had entered the house in 10 years but Partha did not allow them to go into any of the other rooms apart from the living room where they were all seated. The door to Partha's bedroom - where his sister's and dogs' skeletons were discovered on Thursday - adjoining the living room was sealed.

"We had no clue that Debjani had died. So my husband asked about her. Two of Partha's friends also asked about her and the two dogs. His father (Arabindo, 77) said that Debjani was at an ashram but Partha lost his cool and began shouting at his father and all of us," said Mukti.

According to sources, the De family has been living at 3 Robinson Street for the last 80 years after Partha's grandfather Gadadhar bought the 120-year-old house spread over a little less than an acre.

Partha's father Arabindo, an engineer, had left Calcutta after studies and spent almost all his work life outside the city - with many years in Mumbai and Bangalore. He had taken voluntary retirement from Alfred Herbert India Ltd, an industrial machinery manufacturing company, in 1988 and came back to Calcutta the year after.

Arabindo, wife Arati, and daughter Debjani moved into the first three floors - son Partha was away in the US working for an IT firm - while another part of the building was occupied by his younger brother Arun's family.

"Within a few years of their arrival, things started souring between the two brothers," said a neighbour.

While Arati ran a creche on the first floor of their house, Debjani took up a job as a music teacher at Don Bosco, Park Circus.

Life in the De home changed drastically, said sources, following the death of Arati in 2005. "She was suffering from cancer and died within a few months of diagnosis. From then on, the De father and daughter became reclusive and hardly ventured out of their home.

"Two years after his mother's death, Partha left his job and came back to the city. He too rarely left home and so the three hardly had any touch with society," said a neighbour.

Harendra Hansda, the security guard deployed outside the house for the past two months, said that the family did not have any domestic help and no visitor was allowed in.

"A week ago, a delivery boy had gone up to their house door while I had gone out for a cup of tea. Parthababu immediately came down and began shouting at me and threatened to sack me immediately. I apologised but he refused to calm down and kept on muttering 'get out'," Hansda said.

The security guard revealed that Partha regularly ordered home-delivery food - ranging from pizza to rice and curry. "A boy from a nearby hotel used to come with a tiffin carrier and hand it over to me. We would then take it up and Parthababu would take the food and pay for the bill. At times he would return the previous day's tiffin box, which would still be unopened and full. The bills used to come to something around Rs 450," said Hansda.

Neighbours recounted how before his wife's death Arabindo would spend a lot of time at some of the prominent social clubs in the city. "He regularly used to drive his Maruti Esteem to either Tollygunge Club for golf or to Calcutta Club," said one.

"I didn't know him personally, but he seemed to be well-liked. He became a member of Calcutta Club in 1994 and would mostly come to the club on Fridays. I hadn't seen him in the club for quite a while," said Calcutta Club president Suvojit Guha.

On Thursday, the Maruti Esteem remained parked outside the De home with its owner, his wife and daughter dead and his son in custody under medical supervision.

"For the last few years, the car has just stood here. A mechanic from a nearby petrol pump would come, clean the car, start it or take it for a round and then leave it back here," said a neighbour.

Both Debjani and Partha had done their BTech from Rajabazar Science College, family members said.

Till a few years ago, Debjani was the only link between the De brothers and often came over to Arun's house to spend time with her grandmother, Santi Devi. But when Santi Devi died around seven months ago, Arabindo, Debjani and Partha did not even come to pay their last respects, family sources said.

One of Debjani's former colleagues at Don Bosco, Park Circus, confirmed to Metro that she had worked at the school as a music teacher "some eight-nine years ago". She was recruited as a music teacher for the junior school and would teach vocals from kindergarten to Class V.

"She could play the piano well and would teach hymns and other English songs to the children," said the colleague, adding that Debjani left the job in 2007.

A neighbour recounted her last chat with Debjani many years ago. "She was saying she did not want to get married and wanted to become an ascetic. I thought she was under stress but after that we had never met although we live in the same compound," she said.

Another neighbour added how he had seen Partha carrying home two puppies, both black Labradors, a few years ago. "When they were young, we would see them playing in the garden behind the house but at least for the past two years, I don't remember spotting any of them," he said.

Everyone from the security guard to neighbours to relatives had one word to describe Partha: "eccentric".

"About a year ago, there was a stench coming from their house. I asked Partha what was it and he said that one of the dogs had died and he had kept the corpse in the balcony for three days. I was shocked and told him to immediately get rid of it. The stench subsided after that and I thought he must have buried the dog but today I realised that he had kept it in his room all this while," said a neighbour.

Psychiatrists said the tragic sequence of events in the house seem to suggest an isolated family beset by severe mental illness that for some reasons spiralled out of control. A detailed psychiatric evaluation of Partha would be required, they added.

MACABRE TURN OF EVENTS AT 3 ROBINSON STREET