ATM customer Janet Royster said she was used to looking out for suspicious people around the ATM, but not devices.
"[My] card has been replaced already because of some compromised data the credit union found earlier this year, so it's a little scary," she said.
Authorities said ATM skimmers record data from the magnetic strips on the back of financial cards and that information is used to manufacture counterfeit cards. Then the cardholder's PIN number is obtained by a hidden camera.
Police said suspects use the counterfeit cards to make purchases or withdraw funds from the accounts of victims.
Skimmers and cameras are often left in place for a short time period and removed before fraud is detected.
"It sounds like it's pretty high-tech that you wouldn't even know," ATM customer Terry McLean said.
Officials are advising ATM users to closely examine ATM card slots to make sure nothing appears to be attached to the front of them.
They also said not use an ATM if the card reader appears to be added on, to fit poorly or to be lose. Avoid device instructions that say things like "Swipe Here First" or "Use This Machine Only."
"Of course it makes you nervous," McLean said. "My thing is you just got to be careful."
Raleigh police said they don't know how many victims of skimmers there are.
Victims who find unauthorized transactions should immediately report the activity to police and to their bank.
"It's going to change the way you look at everything now," Royster said. "We've all got to be incredibly cautious."
Anyone who anything about the crimes is asked to call the Raleigh Police Department's Detective Division at (919) 996-3555 or Raleigh CrimeStoppers at (919) 834-HELP. CrimeStoppers pays cash rewards for anonymous tips that help solve cases.
