"We kept five foreigners with nearly identical appearances under surveillance for the past few days. We are nearly confirmed that at least one of them - an east European - is one of the culprits," a police spokesman said.
Dhaka Police's Counter-Terrorism and Transnational Crime unit chief Monirul Islam, however, did not name any country but said all the five were nationals of different east European nations.
But he said police was likely to detain the key suspect any time and launch an investigation if any bank official was involved in the fraudulence.
Bank officials said the fraudsters installed skimming devices on February 7 and withdrew money from personal accounts of a number of people on February 11.
Today's development came after Bangladesh Bank, three commercial banks and police analysed video footage of four ATMs from where at least 2.5 million Takas (USD 31,000) were skimmed off.
A central bank spokesman earlier said they believed at least two foreigners were directly involved in the crimes.
Bangladesh Bank said victims of the fraudulence would be compensated with the EBL assistance tomorrow.
