CLEVELAND — Law enforcement agencies across the state are trying to figure out who is responsible for a pin pad scam at several Giant Eagle stores.

U.S. Secret Service Special Agent Blaine Forschen is part of the team investigating the incidents at the Giant Eagle stores.

He said what makes this crime so dangerous is that the skimmer devices are almost impossible to spot with the naked eye.

“Businesses rarely realize that they’re being skimmed, or they were skimmed,” Forschen said.

And that’s what it appears to have happened at the Giant Eagle locations. The store says it found the first skimmer at a store in Central Ohio, prompting it to inspect all the pin pads in its stores.

The investigation uncovered four more skimmers.

“Currently we have two good pictures of people and we’re trying to identify who they are and we suspect that possibly there’s more than just two,” Forschen said.

But while Forschen says it’s tough to spot the devices itself, it’s important for customers to keep an eye out for suspicious behavior.

The store said those who swipe their cards are at more of a risk than those who use the tap or chip features on their cards.

If you've shopped at those stores and are worried about being a victim, closely watch your accounts for fraud.

The Franklin County Auditor’s Office said it conducted several sweeps for skimmers at stores across the county over the past year, but no skimmers turned up during any of those sweeps. It did note that the Giant Eagle in Columbus that’s in the middle of this investigation is not part of the Franklin County Auditor’s Jurisdiction.