Thieves have stolen money through unauthorized ATM transactions more than 30 times since Sunday, suburban police departments say.
Buffalo Grove police said they've fielded 20 complaints from residents who've said they've lost thousands of dollars.
"We are trying to get those cases together and find out is there a commonality, is there a store involved, is there a certain ATM involved, is there a certain bank involved, and find out how these cases are all linked up together," said Buffalo Grove police Cmdr. Steve Husak.
There have also been at least 15 similar incidents reported in Wheeling, where account-holders noticed money missing from their accounts. Others have been reported in Harwood Heights.
Police said they believe the thieves are using skimming devices that can capture the card's account information from its magnetic stripe, then watching or recording a person as they enter their Personal Identification Number. The account information recorded from an authentic card can then be embedded on another card, such as a blank store gift card.
The commonality in most incidents is that the amounts withdrawn is usually $500 or $503 because most debit accounts only allow a maximum withdrawal of $500 and most ATMs charge a $3 fee.