Forensic experts examine the front door of the Das apartment on Friday. Picture by Pronab Biswas

Thirty-six hours after a gang of 15 looted cash and jewellery worth Rs 20 lakh from the Das household in Kanchrapara, police are only sure about the operation being a planned one.

The investigators still do not know whether house-owner Bimal Das’s wife Chandana was pushed off a third-floor balcony or she toppled over while trying to resist the dacoits. The 42-year-old woman bled to death on the road.

The third-floor balcony was still under construction and was not fenced.

According to the police, the nature of the operation suggests insider involvement. “It seems somebody had passed on the information that a lot of jewellery was stored in Bimal’s shop on the ground floor. Several orders had been placed in the marriage season,” said an investigator.

“The dacoits had switched off the electricity mains on the ground floor and entered the shop with flashlights in hand. They moved freely around the house and knew exactly where the cash and jewellery were kept. Seasoned criminals were involved in the operation. They left the area in small groups,” said another officer.

“We are interrogating the employees of the jewellery store, the security guards and the helps,” added the officer.

The investigators also spoke to the family members on Friday afternoon.

Gloom hung over the four-storeyed house, in the middle of a marketplace, as Bimal, his 11-year-old son Bidyut and 17-year-old daughter Barsha struggled to cope with the tragedy.

“I have lost everything,” mumbled Bimal, sitting in his bedroom with traders from the area, who observed a strike to protest lax policing.

“We are all scared and want the dacoits to be arrested immediately,” said A. Agarwal, the secretary of the local traders’ body.

The government on Friday sought a report from the police. “I have never heard of such a gruesome incident,” home secretary Prasad Ranjan Ray said at Writers’ Buildings on Friday afternoon, after a discussion with the director-general of police, A.B. Vohra.