A worldwide gang of criminals stole $45m (€34m) in a matter of hours by hacking their way into a database of prepaid debit cards and then draining cash machines around the globe.
An outmoded US card technology may be partly to blame.
Seven people have been arrested in connection with the case.
Prosecutors said that thousands of thefts were made from ATMs using bogus magnetic swipe cards carrying information from Middle Eastern banks.
Prosecutors said the gang moved with astounding speed to rob financial institutions around the world, working in cells including one in New York.
One of the suspects was caught on surveillance cameras, with his backpack increasingly loaded down with cash, authorities said.
Others took photos of themselves with giant wads of money as they made their way up and down Manhattan.