Athens-Clarke police have heard complaints about the thefts for months.
But now more and more bank customers are walking into law enforcement offices in Oglethorpe, Madison and other outlying counties to complain about bogus charges on their debit and credit cards.
Madison County investigators are working with police in Athens-Clarke County, where Detective Beverly Russell has been investigating a series of similar thefts for months.
Both agencies have also sought help from the U.S. Secret Service, Detective Russell said.
In recent thefts in Madison County, only debit card customers were targeted, but elsewhere thieves also are using credit card numbers, Ms. Russell said.
The thefts appear to be part of a larger, nationwide crime spree, Detective Russell said.
Bank customers' credit and debit card numbers probably weren't stolen here; thieves could be working almost anywhere in the world, she said, likely higher up in one of the enormous electronic systems that process credit card charges and bank withdrawals.
Because the fraud seems to begin at a high level in the credit and debit card system, bank customers can do little to protect their information, other than stop using credit and debit cards.
But customers can minimize losses by keeping a close eye on their transactions, Detective Russell said.
If a customer can catch the first one or two false charges quickly and report them to the bank, then he can prevent more thefts, she said.
Investigators in Richmond County say they have yet to see this type of crime here, but that it's only a matter of time before it hits.
"Whatever happens up there will trickle down here before long," Sgt. Randy Hayes said.
Staff Writer Adam Folk contributed to this report.