A customer has allegedly embezzled Tk4.54 crore from Islami Bank by exploiting a loophole in its credit card system and making unauthorised transactions beyond his approved credit limit.
Police arrested the man and his wife in Bogra after a 36-hour operation.
Naogaon Superintendent of Police (SP) Mohammad Tariqul Islam disclosed the matter at a press briefing at his office on Saturday afternoon.
The arrestees are Shahidul Islam Ripon, 37, of Akkelpur Madhyapara in Badalgachhi upazila of Naogaon, and his wife, Maliha Tabassum Nishi, 28. Shahidul was an investment client of Islami Bank's Naogaon branch.
The SP said the bank issued Shahidul a Khidmah credit card with a credit limit of Tk1 lakh in 2015.
He allegedly exploited the card and the National Payment Switch Bangladesh (NPSB) network at Pubali Bank's ATM and CRM booths to carry out repeated unauthorised fund transfers.
Initially, he transferred less than Tk1 lakh per transaction, but later increased the amount to Tk2.5 lakh, exceeding his authorised credit limit.
Between June last year and November 9 this year, he allegedly embezzled Tk4,54,13,000 through more than 420 transactions.
Police launched an investigation after the bank authorities lodged a complaint, and a case was filed with Naogaon Sadar Model Police Station.
Following a 36-hour operation in different areas of Bogra Sadar, police arrested Shahidul and his wife.
Acting on information provided by the arrestees, police recovered Tk15 lakh in cash, seven ATM cards and three cheque books concealed in a wooden wardrobe in their bedroom in Bogra.
SP Tariqul Islam said the couple admitted their involvement in the fraud during preliminary police interrogation.
They told police that they had spent around Tk1.5 crore of the embezzled money on purchasing land in Bogra, while the rest was used to maintain a lavish lifestyle.
Police are continuing their investigation to determine whether any bank officials or other individuals were involved in the fraud.