Krishnagar, Nov. 7: A gang of robbers wiped out almost the entire family of retired headmaster Sanjib Biswas in a raid on his house early this morning.

They murdered 60-year-old Biswas and his brother Chiranjib. Saroma, Chiranjib’s wife, is fighting for life in a hospital. The gang looted the house after trying to annihilate the family.

The incident took place at Khalboalia village under Krishnagunj police station in Nadia, about 120 km from Calcutta.

Preliminary investigations have revealed that the operation might have been carried out by the local land mafia to grab Biswas’s property of nearly 25 bighas.

Police said Biswas, who retired last year as headmaster of Khalboalia High School, his wife Jyotsna, 45, businessman brother Chiranjib, 55, and his wife Saroma, 40, were at the house when the gang struck around 1.30 am.

The killers barged into Biswas’s single-storey house, breaking open the main entrance.

One of the intruders fired at him point blank. Two bullets hit him in the belly and he slumped to the floor.

His screams sent Saroma, Jyotsna and Chiranjib rushing to the spot. They tried to resist in vain. The gang hacked Chiranjib and Saroma with sharp weapons. One of them took a shot at Chiranjib.

Seeing Chiranjib and Saroma writhing in pain, Jyotsna gave in. “I was too shocked to do anything,” she said.

After the mayhem, the group looted the house and left under cover of darkness. Jyotsna called the neighbours and the injured were taken to Saktinagar Hospital.

Sanjib and Chiranjib were pronounced dead on arrival. Saroma was said to be in a critical condition.

The police said the raid was planned as the gang appeared to be aware that Biswas was preparing to shift his family to Chakdah in North 24-Parganas. He wanted to sell the land before moving.

“Although the attackers took away some valuables, we suspect it was the handiwork of the land mafia,” said an investigating officer.

Nadia superintendent of police R. Rajsekharan said four people have been detained. “Raids are being conducted on the basis of information provided by them.”