ST. LOUIS (KTVI) – The latest ATM skimmer device that can clone your bank debit card data is made of thin plastic and hidden inside the card reader.

”I was surprised how small it is,” Detective Andre Nikolov with the St. Louis Metropolitan Police Department told NewsNation affiliate KTVI. “And that they were homemade.”

Nikolov uncovered an alleged crime family connected to the latest device.

A picture of a compromised system shows how hard it is to detect. In one example, you can see a slot in the back where criminals hide a pinhole camera. The camera allows them to record you entering your PIN.

“After going through different video, coordinating with different agencies all over the country, we found that it was a Romanian crime family,” Nikolov said.

St. Louis has been targeted by Romanian organized crime. Last year, St. Charles police nabbed a group of alleged Romanian jewel thieves. The year before, Arnold police busted a Romanian sleight-of-hand theft ring.

The latest St. Louis police sting found the Romanian ATM skimmer suspects working out of a short-term rental home in north St. Louis County. Police arrested two people who are now charged. Three others were captured in Texas. Two other suspects may have left the country.

“They also use a lot of fake identification, so their names are different,” Nikolov said. “They might actually get arrested in one name, but that’s not actually who they are.”

In addition to warning your bank of a strange charge, Nikolov recommended notifying police: “If we don’t know about it, we can’t hold people accountable for it.” That includes a small charge, which the detective said could be a warning.

“A lot of times what these guys are doing is they’re going to use the ATM and they’re doing inquiries just to see how much money is in there,” Nikolov said.

What is a skimming scam?

Skimming scams are targeted at people using ATMs, gas pumps, or credit card readers at retail outlets, the FBI says. The scammers carefully craft devices that look like legitimate card readers, which they then attempt to “blend right in” to the actual machine, according to the FBI.

That device can then store the victim’s information for the criminals to retrieve or it be sent to them.

How can you spot a skimming device?

The FBI recommends inspecting a card reader before using it and looking for any loose parts, damage, scratches or defects in the adhesive tape holding it. If you give the skimmer a light shake and it feels loose, tell an employee.

To prevent cameras from capturing your passwords, the FBI recommends users cover the keypad with one hand while punching in the PIN with the other.

Police in Concord, New Hampshire, recently warned that some scammers will try to keep you from using the card’s chip by blocking that slot on a machine, forcing you to swipe the card — a method that makes it easier to steal your information.

If you are concerned an ATM or other card reader has been tampered with, authorities recommend notifying management at the business or bank.

Michael Bartiromo and Nick DeGray contributed to this report.