HINSDALE, Ill. (CBS) – Authorities were warning Chicago area residents about scammers using skimming devices on ATMS to steal money from people’s bank accounts.

CBS 2’s Pamela Jones reports police said a group of crooks has been using ATMs at two banks in Hinsdale to make unauthorized withdrawals from customers’ accounts. There could be 100 or more victims.

“In most cases, it’s five- or six-hundred dollars that’s been taken from these accounts,” Hinsdale Police Chief Bradley Bloom said.

Police believe the criminals tampered with the ATMs at two downtown Hinsdale banks – the Northern Trust branch on Washington Street, and the Hinsdale Bank & Trust on First Street.

The crooks apparently fastened a hood on top of the ATMS at the banks, covering the skimming devices used to record customer information from the magnetic strips on credit and debit cards used at the machines.

The suspects would then load data collected by the devices onto phony cards, and withdraw money from the victims’ accounts.

Two CBS employees – CBS 2 anchor Rob Johnson and CBS News correspondent Dean Reynolds – were victims of the scam.

Reynolds said he first noticed something wasn’t right when his ATM card was rejected.

“It was rejected twice two days ago, and then I went to the Northern Trust bank that I bank at, and it was rejected there,” he said.

Johnson said he wasn’t in town when someone withdrew money from his account at a Chicago ATM.

“I certainly wasn’t on the North Side of Chicago … making four withdrawals on a Saturday,” he said.

Northern Trust launched a debit card investigation, listing $1,000 worth of fraudulent withdrawals from Johnson’s account; three from a Chase ATM on Lawrence Avenue, and one from a Citibank machine on Central Avenue.

“The money’s not the issue. It’s the fact that you feel violated,” Johnson said.

Reynolds said, “It’s unsettling when you think that this isn’t like Joe’s Bank, or something. This is Northern Trust.”

The banks did not respond to requests for comment, but Northern Trust has assured customers if they can prove they are victims of fraud, they will get their money back.