A retired state government employee hanged himself in his Sodepur apartment early on Monday after allegedly trying to kill his wife and their only son by stabbing them.

The wife and the son escaped death and have been admitted to hospital with serious injuries. A suicide note found in the apartment states that the family is under debt and is unable to repay it.

Biplab Banerjee, 65, lived with wife Tandra, 55, and their 35-year-old-son Suman, who is unemployed, in a third-floor apartment in the Ganga Jamuna Bhagirathi housing complex on Nilgunge Road near Sodepur, on the northern fringe of the city.

Biplab had retired as clerk in the consumer affairs department. Suman is a math graduate and gives private tuition.

Around 6am on Monday, a few residents in the Ganga cluster of the estate were alerted by a youth's cry for help.

"We realised that the screams were from flat 3E on the second floor and knocked on the door. The door was locked from outside, so we had to break it open," said a member of the residents' committee of the housing complex, refusing to be named.

On entering the Banerjee apartment, the residents saw Tandra, a homemaker, lying on bed with a deep cut on her neck and stab wounds on her arms. "She was gasping, while Suman was bleeding from his throat and had his right vein slit," said another member of the residents' committee.

The neighbours broke open the door of an adjoining room and saw Biplab hanging from the ceiling fan.

"We immediately alerted the police and took Tandra and Suman to the nearby Balaram Seva Mandir hospital. The cops later brought down the body," a neighbour said.

"My husband suddenly began to slash me in the morning and gagged my mouth. I passed out and regained senses after our neighbours broke into the apartment," Tandra said.

Suman apparently told the police his father had slumped to the floor after slashing him.

The police found a suicide note in the room where Biplab was found hanging. "The note mentions the family's debt. We are investigating all possibilities," said Ajay Thakur, deputy commissioner, detective department, Barrackpore commissionerate.

"The suicide note purportedly written by Biplab Banerjee mentions that the family owed around Rs 99,000 to 12 money lenders in the area," an officer of Khardah police station said.

"The money lenders used to visit the apartment often and demand the money. We have learnt that the elderly man had tried to sell his flat a few months ago."