The US Attorney's Office in Manhattan confirmed on Thursday that it had charged 37 individuals for their role in a scheme that used computer viruses to steal more than $3 million from banks.

Most of the charged individuals are from Russia and East European countries. They opened hundreds of bank accounts to launder money transferred from customers who had been infected by the crimeware.

All the charged individuals used to act either as money mules that assisted transfer stolen money out of the US, or individuals who recruited and managed them.

The individuals opened several bank accounts in different banks, including TD Bank, JPMorgan Chase and Bank of America, using assumed identities. These fraudulent accounts were used to get tens of thousands of dollars stolen from various small business accounts.

The charged individuals used to send a computer virus, called Zeus Trojan, which is capable of infecting a computer and recording the user’s keystrokes and send them back to the hacker.

The officials said that the virus was allegedly providing the hacker with the usernames and passwords as the victims used banking websites.

The charges that followed a year-long investigation were filed by the US Attorney's office in Manhattan in 21 different cases. Twenty of the defendants have already been taken under arrest, while the remaining seventeen are still at large.