"Skimming is a technique that criminals use to gather information either on a credit card or an ATM card off of the magnetic strip," Secret Service Special Agent in Charge Cindy Wofford said.
Wofford says one certain skimming device appears to have been placed on two Wells Fargo ATMs: on January 5th on an ATM in Center Square and the next day on an ATM in Ambler - both on Skippack Pike.
Investigators say the crime was caught so early that the thieves did not have the chance to use the stolen information.
Another skimming technique is attaching a side panel with a small camera on the ATM.
"This is the pinhole camera that actually watches the customer put in the pin number to the ATM," Wofford said.
These kinds of skimming devices were found at TD Banks in the 2700 block of Street Road in Bensalem and the 700 Block of East Street Road in Feasterville less than two weeks ago on January 11th.
Surveillance video shows the devices being placed there on January 10th around 6:00 a.m.
TD Bank officials tell Action News they believe these devices did not have the ability to transmit data back to the fraudsters.
But that's not the case in the most recent skimming incident Action News just told you about this week at a TD Bank in Medford, New Jersey.
Police know of 15 victims in Medford, but there may be hundreds more who do not yet know they could also be victims of fraud.
Medford police say over the weekend, customers who used the ATM at the TD Bank branch on Stokes Road began calling saying their accounts had been compromised, with transactions appearing in the New York City and Connecticut areas.
An investigation by TD Bank determined that back in mid-December, culprits installed an illegal skimming device on the ATM - a device that is very difficult for a customer to detect.
Officials say the device was on the ATM for 24 hours before it was removed. Surveillance images released Wednesday showed one man installing the device on December 16th and another man removing it on December 17th.
In that time frame, many customers' debit card information may have been stolen.
TD Bank says it is contacting consumers who may have been affected by skimming and will work with them directly to address and correct any issues as quickly as possible.
In the meantime, here's how you can protect yourself: