In 2007, First Bank of St. Louis lost about $5 million in fraudulent ATM withdrawals to someone who had hacked four iWire Prepaid Card accounts.

Surveillance video from a Washington Mutual bank branch in Brooklyn, N.Y., where some of the unauthorized withdrawals were made, showed a Caucasian man in a dark baseball cap emblazoned with the words "Top Gun" and a star and wings symbol, as well as a tan-colored sweatshirt or jacket with a dark front panel and dark trim at the zipper and collar, according to the affidavit of FBI special agent Albert Murray.

Murray said that the same individual, wearing the same clothing, also appeared in ATM video surveillance at other Brooklyn banks at times consistent with the First Bank withdrawals.

An individual wearing the same "Top Gun" baseball cap and clothing appeared in Washington Mutual surveillance video captured in February 2008. The individual withdrew money using ATM personal identification numbers taken from a compromised Citibank server that processes ATM withdrawals at 7-Eleven convenience stores. Authorities estimate that the robber stole $750,000 that month, according to Murray.

The fact that hackers were able to get PINs raises questions about the security of financial infrastructure. Such data is supposed to be encrypted.

Since 2005, authorities had been monitoring the activities of a carder -- someone who buys and sells stolen credit card numbers online -- known only by an undisclosed nickname. At some point, the user of this nickname posted an ICQ instant messaging user identification number (UIN) in an online forum used for carding. The ICQ White Pages indicated that the user of the ICQ number in question had identified himself as "Yuri," a 29-year-old from Brooklyn.

At this point, investigators turned to Google.

"A Google search for the UIN found that this ICQ UIN was identified with a ham radio operator who uses a specific radio call sign," Murray's affidavit says. "A Google search for this call sign led to Web sites for ham radio enthusiasts, such as www.hamgallery.com and www.grz.co.il."

At those sites, investigators found photographs showing "Yuri" wearing "the same tan-colored jacket or sweatshirt as the individual in the Washington Mutual and Citibank ATM videos," Murray's affidavit says.

A Google search also led to a link to a Federal Communications Commission enforcement letter sent to the amateur radio operator using the radio call sign associated with "Yuri." The letter, which detailed various ham radio rules violations, was addressed to "Yuriy Ryabinin" in Brooklyn.

On Friday, a Brooklyn grand jury returned a three-count indictment against Yuriy Ryabinin, Olena Rakushchynets, and Ivan Biltse for conspiracy to commit access device fraud, access device fraud, and obstruction of justice.