Hackers Bangladesh bank
Hackers initially breached Bangladesh Bank's online systems and stole credentials for payment transfers iStock/Getty

The Bangladesh central bank has reportedly retrieved $15.25m (£12.2m) of the $81m stolen in an unprecedented cyberattack against the financial institution in February. Officials who are now working to retrieve more of the funds believe at least $30m more could be recovered imminently.

In what is believed to be the largest financial cybercrime in history, hackers targeted the bank's access to the Swift messaging system to transfer $1bn from its account at the New York Federal Reserve. Ultimately, $81m was stolen after a spelling error alerted authorities to the hack.

The hackers – whose identities remain unknown – transferred the stolen money to four accounts at the Rizal Commercial Banking Corporation based in the Philippines. To move the stolen cash, it is believed it was laundered through casinos in the region.

On Friday (11 November 2016), $15.25m was returned to the bank after casino boss Kim Wong, owner of the Eastern Hawaii Leisure Company, surrendered the stolen money to the government. The casino boss handed $4.63m and 488m pesos ($10.05m) he obtained from two "Chinese high rollers".

In September, as reported by local media, a court in the Philippines ruled that the money originated from the Bangladesh central bank. Wong, after handing the funds to the Philippines' anti-money-laundering council, denied playing any role in orchestrating the crime or playing a role in the crime itself.

"Two foreigners brought in the $81 million," Wong told philstar.com. "One of them has been going in and out of the country for a long time already, and is known as a junket agent and a high roller," he added, naming the two individuals as Sua Ha Gao and Ding Zhize.

Speaking to Reuters, officials of the central bank believe they can retrieve the rest of the cash. "We are hoping to get back around $30m that remains frozen," said Abu Hena Mohammad Razee Hassan, head of the bank's financial intelligence unit, told Reuters in a statement.

Another source, granted anonymity because they were not authorised to speak to the media on the cyberheist, told Reuters: "We are expecting to get a favourable verdict from Philippines' Supreme Court as it has already been proved that $81m is our money."

According to GMA News Online, an outlet based in the Philippines, a "high-powered" delegation from the Bangladesh central bank is to travel to Manila at the end of November in a bid to speed up the process of recovery by meeting with President Rodrigo Duterte.

"We are optimistic to recover the rest of the money and we are working with the Department of Justice and Anti-Money Laundering Council (AMLC) in this regard," said John Gomes, Bangladesh ambassador to the Philippines.

Previously, as facts about the scope of the hack came to light, the central bank was criticised for a lack of adequate cybersecurity standards. Investigators probing the hack found the bank was using $10 routers to connect to the Swift system and, in some cases, not using firewalls.

Bangladesh police said it had identified 20 "foreign suspects" – 12 Philippine nationals and eight Sri Lankans – believed to have played a role in the incident.

For its part, Swift – the secure system that connects more than 10,000 financial institutions globally, claims it was not compromised in the attack.