Some Bangladesh central bank officials deliberately exposed its computer systems and enabled hackers to steal US$81 million (A$108 million) from its account at the Federal Reserve Bank of New York in February, a top investigator in Dhaka has revealed.
The comments by Mohammad Shah Alam of the Dhaka police are the first sign that investigators have got a firm lead in one of the world's biggest cyber heists. Arrests are likely soon, he said.
Last week, the head of a Bangladesh government panel that investigated the heist said five bank officials were guilty of negligence, but they were only unwitting accomplices.
"Bangladesh Bank's SWIFT network was made insecure by some bank employees in connivance with some foreign people," he said.
"They knew what they were doing."
He said investigators were now trying to find out how the mid-ranking officials were connected to the hackers and whether they benefited financially from the heist.
Asked if the officials would be arrested, Alam said "we are very close to it."
Bangladesh Bank spokesman Subhankar Saha declined to comment.
Another investigator, who declined to be named, said more than 100 Bangladesh Bank employees had been interviewed in connection with the heist, and some were barred from leaving the country.
The hackers used fake orders to order the transfer of nearly US$1 billion from Bangladesh Bank's account at the New York Fed, using the international SWIFT payments network.
Many of the transfer orders were blocked or reversed but US$81 million was successfully transferred to four fake accounts in a branch of Rizal Commercial Banking ) in the Philippines. Most of the funds then disappeared into Manila's loosely regulated casino industry.