The four-storey building with dark windows at 21C Atal Sur Road in Tangra is the only impartial witness to what transpired inside.

No one has switched on the lights in the building after Monday evening.

With the help of accounts from personnel who have been inside to probe the deaths of two women and a teenage girl there, The Telegraph tries to decode the anatomy of the building where the families of Pranay Dey and Prasun Dey lived.

The building

Ground floor

The ground floor of the four-storey building has been turned into garage space with an adjoining lounge, which police said was big enough to accommodate a badminton court. Multiple badminton shuttlecocks found stuck in the fence have made the police believe the family members used to play badminton in the ground floor lounge.

Mezzanine floor

A small room on the mezzanine floor looked like an office. It had files and other documents.

First floor

Has three bedrooms, including two with false ceilings, one relatively small study and a washroom, sources said.

Each bedroom has a split air-conditioner and an attached balcony wrapped
with a grille. The windows have tinted glass. The bodies of Romi Dey, Sudeshna Dey and Priyambada Dey were found in the bedrooms on this floor.

Second floor

The second floor has a dining hall, a kitchen, a bedroom with a false ceiling and a washroom. The only window air-conditioner in the house is fitted in the dining hall.

The DVR (digital video recorder) attached to CCTV cameras, is placed in the dining hall, sources said.

Although the three bodies were found on the first floor, there were blood stains in the bedroom on the second floor.

Third floor

The third floor and the terrace remain locked, sources said.

What the investigators found inside

CCTV cameras

The police said the building has as many as 18 cameras.

When investigators entered the Dey residence, they found all the cameras had been disconnected. Sources said the last recording found on the DVR was of Sunday evening (February 16).

“This clearly indicates the cameras were deliberately switched off not to leave any trace of what was going to happen inside the house,” said detective department officer.

Blood stains

Blood stains were found in all three bedrooms on the first floor where the three bodies were found.

On the second floor, too, blood stains were found in the bedroom, in the dining area and in front of the washroom.

“There were blood stains almost all over the house. It was very clear that there was a lot of struggle and people ran around in the house,” said an investigator.

Eight mobile phones

The police found eight mobile phones at the residence. All eight were in flight mode, an officer said. No calls can start or end if a phone is in flight mode.

KMC documents

Investigators have found documents in the house that show that the family had withdrawn their trade license from the Kolkata Municipal Corporation three months ago.

The police have also found details of the family’s leather gloves business and their exports to Germany and the US.

“They also have a factory in North 24-Parganas. Earlier, they had a property in Santiniketan and used to do silk business there. That business is closed now,” an officer said.