A few weeks ago, an American Express security official placed an urgent call to New York City-based Secret Service agent Tim Raymond. Someone in Miami had racked up at least a half-million dollars worth of fraudulent charges against more than 100 American Express accounts. The cards hadn't been stolen, so they had to be counterfeits--very good ones, since they had zipped past the security screens in the computers of the giant charge-card company.
The bad guys in Florida covered their tracks expertly, but the American Express computers spat out a curious fact. Every one of the victimized cardholders had recently...