Some residents have noticed hundreds of dollars drained from their bank accounts.
Police are warning people to keep a close watch on their accounts for illegal activity.
Thieves are targeting consumers in northwest suburban Wheeling and Buffalo Grove.
Police have found that only the debit card numbers are being used, and the cards themselves are not being stolen.
Wheeling and Buffalo Grove police have complaints from dozens of residents and both suburbs expect many more victims.
Debit card numbers and PINs were somehow stolen over the weekend when victims used their cards to buy merchandise at local businesses.
By Monday, large ATM withdrawals were showing up on victims' bank statements.
All week the Wheeling Police Department has been taking complaints from close to 100 wheeling residents who say they are victims of debit card fraud.
"When I went to check the first account, which was our checking account, I come to find out that there were two withdrawals made on Septmber 13th for $503 a piece that came out of an ATM machine from Citibank in Woodland Hills, California," said victim Barbara Bliefernich.
Bliefernich immediately called her bank and then filed a report with the Wheeling Police Department.
Jeanette Angarita and Marilyn Erlich also paid visits to the police on Wednesday.
Angarita says that $1,006 was taken from her account within two days, and the she is concerned that those responsible have not been caught.
"It's terrible," said Angarita. "They'll be investigating it at the bank... in the meantime, they're gonna replace it, but I can't use my debit card anywhere."
"I was checking my bank account balance on Monday morning and I saw a $500 pending transaction from an ATM, and we don't use an ATM," said Erlich.
Police say the victims all used their debit cards at various local businesses over the weekend. In the following days, they noticed out-of-state ATM withdrawals on their bank statements.
"We're not sure what devices or how it's being done," said Wheeling Police Deputy Chief John Teevans. "We know that there is a retailer that is being looked at."
Police are not sure if an individual or a nationwide computer hacking network is responsible for the fraud.
"We are not sure how big the problem is," said Teevans. "Right now, we're aware of the states within the United States. Is it going to go abroad? I don't know."
While the banks are reimbursing the victims, Bliefernich said she doubts she will use a debit card again.
"If I'm going to have to shop, I'm probably going to be paying with cash," said Bliefernich.
Other victims say they are now going to use the credit portion of their debit card instead of using a PIN.
Northwest suburban police departments are working with the FBI to crack the case.
Even if your bank reimburses you, police urge all victims to file a police report.
Some banks are reimbursing the fraud victims, but in some cases, there is a ten-day waiting period resulting in insufficient funds causing bounced checks.