Salt Lake: The tenants of an 80-year-old former ONGC executive allegedly cleaned out his bank accounts containing more than Rs 35 lakh by forging his signature on stolen chequebooks and using a duplicate debit card.

Based on a complaint by a sister of Dilip Majumder, who lives alone in his three-storey Salt Lake house, police on Monday arrested Anupam Das, 49, and his wife Aditi Das Mukherjee, 42, on charges of theft and cheating.

Dilip's sister had written to Bidhannagar police commissioner Gyanwant Singh about the alleged swindle, saying the accused took advantage of her brother's age and illness. Dilip, who had retired from the ONGC as a regional director, is battling cancer.

The complaint mentions that Anupam had introduced himself as a software engineer working for a multinational company with an office in Sector V. He moved into the second floor of the house last March with his wife and their daughter.

The deputy commissioner of the detective department in Bidhannagar, K. Sabari Rajkumar, said tracing the money trail took time because Dilip has accounts with multiple banks and post offices. "We had to seek out details of every banking instrument and that took time. We had started a case as soon as we received the complaint."

Anupam and Aditi are to be produced in court on Tuesday.

Rupa Majumder, a niece of the victim, accused the tenants of stealing chequebooks, passbooks, an ATM card and several documents pertaining to shares and mutual funds from one of the almirahs in the house.

"Since my uncle has cancer, I had kept his ATM cards and chequebooks in the house so that money for his treatment could be withdrawn whenever needed," said Rupa, a medical officer in a government hospital.

In July 2017, Dilip had been admitted to a nursing home in Salt Lake. Rupa had then looked for a chequebook in the almirah but did not find it. The passbook for that account was missing too. A visit to the bank revealed that there was no cash left in that account.

Her suspicion of foul play was confirmed when a duplicate passbook with transaction updates showed what had happened. "Imagine my horror when I discovered that Rs 35 lakh had been withdrawn systematically over a few months from just one account," Rupa said.