An armed gang of six looted jewellery and around Rs 1 lakh from the house of former fire services director Barendra Mohan Sen, in Hossainpur, early on Tuesday. They also seriously injured him and his nephew.

Sen received 12 stitches on his head while his nephew, Rabindranath Mukherjee, received 16. One person has been detained for interrogation.

Preliminary investigations suggest the dacoits were from the neighbouring Tiljala area. ?We hope to arrest them soon,? said S.N. Gupta, SP, South 24-Parganas.

The gang struck around 3 am, while the Sens were sleeping on the second floor and Rabindranath in a ground-floor room of their house off the EM Bypass.

The teenager woke up on hearing a noise outside. When he reached the main gate and demanded to know who was there, he was greeted with a volley of abuse. The dacoits ordered him to open the gate.

?They did not wait for him to let them in. They smashed open the gate, barged in and hit Rabindranath on the head with iron crowbars. Hearing his screams, my husband woke up and rushed downstairs. He, too, was hit on the head,? recounted Mamata, Sen?s wife. As Sen and his nephew lay on the ground, bleeding profusely, the criminals broke open an almirah and started stuffing the cash and valuables in it.

?They dragged my husband to the first floor, where I was standing with my daughter and granddaughter. Without uttering a word, we handed over whatever jewellery we had on us. The criminals then left the house, threatening us with dire consequences if we told the police,? she added.

The gang took just 20 minutes to clean out the house. ?After they left, I called up my former colleagues at the fire services, who took me and my nephew to a private hospital,? Sen said.

Ajoy Paul, the doctor who attended to Sen, said: ?Barenbabu was lucky that his eye was not damaged. He has been released but I have asked him to come back for check-ups.?

Neighbours are as shocked at the incident as the Sens. ?We have never witnessed such a brutal dacoity here. The Sens came to the neighbourhood in October. Barenbabu wanted to settle down here after retirement because the place is peaceful,? said Ashish Moitra, a neighbour.

The Sens were awake till late on Monday, busy helping their daughter pack her bags. She is scheduled to leave for the UK, with husband and child, early on Wednesday.