A father-son duo and an accomplice were arrested on Wednesday night for allegedly duping a bank of about Rs 40 lakh.

Pravin Agarwal, 45, his 25-year-old son Ambrish and associate Vinod Agarwal, 44, were charged with withdrawing Rs 39.97 lakh from the Bhowanipore branch of Federal Bank earlier this year.

They duped the bank by providing forged letters of credit from the Salt Lake branch of Karnataka Bank.

The three were produced in court on Thursday and remanded in police custody till November 24. A probe revealed the trio were arrested six months ago on charges of cheating and were out on bail.

“The fraud came to light in March, when the branch manager noticed a discrepancy in the audit report,” said an officer of the bank fraud cell of the detective department.

Cops started a probe after a senior manager of Federal Bank lodged a complaint in March. An investigation revealed that the father and son were involved in several cases of fraud.

“Vinod is a distant relative of Pravin. He helped the father-son duo forge the letters of credit,” said another officer.

Pravin and his son live in Salt Lake while Vinod is a resident of Serampore.

“It seems they managed to withdraw such a big amount with the help of a branch employee. We are also interrogating bank staff members,” an officer said.

In another incident, Gautam Sen Sharma, 43, an employee of Eastern and North-Eastern Frontier Railway Co-operative Bank, was arrested for siphoning off Rs 2.52 lakh from the bank by taking personal loans under three fictitious names.