Test Text1 plain Tonight a high-tech scam that is increasingly common, incredibly easy to pull off, and could be inflicted upon you by the friendly face at your local gas station or fast food... See More
Test Text1 plain Tonight a high-tech scam that is increasingly common, incredibly easy to pull off, and could be inflicted upon you by the friendly face at your local gas station or fast food check-out counter. Police are now turning to an unlikely source to bust these bandits. And here's ABC's Rebecca Jarvis with another look at skimming. Reporter: He may look like an ordinary McDonald's drive-thru attendant. But he's actually a brazen credit card thief caught on tape. I would have never pointed my finger at the drive-thru because you're sitting right there. You're watching them use your card. Reporter: Let's see that again. He's swiping an unsuspecting customer's credit card not once but twice. First the legitimate charge for the food. Then again on a separate device called a skimmer that allows crooks to steal your credit card info from right under your nose. A lesson Richard Norris learned the hard way. He had gotten me three different times. Reporter: He had never given much thought to his morning ritual stopping at McDonald's -- May help you? Reporter: -- For his guilty pleasure. Can I have a large sweet tea, please? Reporter: Until he and his wife noticed mysterious charges popping up on all three of their credit cards. So he was able to skim all three cards at the same location. Reporter: Those golden arches. When the cops checked the security camera, paydirt. They actually were able to catch the individual sliding the card and then grabbing the receipt and handing it to me all in one nice movement. You'd never know that he was doing anything wrong. Reporter: This unabashed face-to-face banditry is more common than you think, and it's not just restaurants. From atms to gas stations, wherever you swipe, criminals could be cashing in. Just ask detective Jeffrey Marshall of the Nassau county police department in New York. Little device. That little device. Could fit in the palm of your hand. You never see it. In the pocket. And the waitress's apron. You don't know. Reporter: These days some electronic skimmers are so advanced that they don't even need a human to operate. He takes the device out of the backpack. Reporter: Detective Marshall showed thus video of a crook modifying an atm inside a convenience store. Watch as he places a fake card slot that contains a skimmer over the real one. In four seconds he has it attached. Wow. Reporter: But he's not done. He then adds a tiny camera to catch you entering your pin. You'd use this atm and that cheat has enough Intel to shop with your credit card and make cash withdrawals straight from your account. This is the skimming device, right here. Yes. Reporter: A scam so easy to pull off detective Marshall let me try it for myself with the deactivated skimmer he confiscated. If I were a criminal and I walked up, this is all I would have to do? Yep. Reporter: Of course we removed the device immediately. So how do the cops stay ahead of the high-tech crook curve? Turns out they're getting help from an unlikely source. The atm cashing was the easiest and best way to make money. And I was making thousands of dollars a day in cash doing that. Reporter: Dan dephillippe is a reformed credit card hacker who got busted and switched sides to avoid prison time. He spent two years training agents in the dark art of skimming. Dephillippe's favorite target -- gas stations. Installing gadgets like this one inside the pump. So this is the reader that would be inside the gas pump. So you would just swipe it through and it would read it right here. Nobody would know the difference. Reporter: When investigators at the Arizona department of weights and measures -- We're here checking for skimming devices. Reporter: -- Found a skimmer inside this gas pump, they decided to fight fire with fire. We inserted one of these little nightvision spy cams in the back of the dispenser. Reporter: And bingo. Here's the view from that camera inside. Apparently showing a man and a woman team caught red-handed. What we have here, we have the guy. And I have the missus. Reporter: They start bickering when they can't find any of their devices. It's almost like a husband and wife team arguing about wherever their skimmer is because somebody got it. And that was us. We got it. Reporter: Law enforcement is still on the hunt for Mr. And Mrs. Skimmer. But in the meantime there are some things you can and should do to protect your digits. If you're fueling up choose a pump near the attendant. Crooks prefer to operate in the shadows. Or you can always pay in cash. At the atm give the machine a good look. If anything appears off, keep on walking. And always remember to cover your hand when you enter your pin. Lastly, no matter where you are, check your account. A lot. Once you report a fraudulent charge, the law says you have no responsibility for paying charges you didn't make. It worked for Richard Norris back in Florida. Thanks to his careful monitoring, that McDonald's drive-thru attendant pled guilty and got two years probation. And Norris still heads to McDonald's every morning for his sweet tea fix. Thank you. Have a nice day. Reporter: For "Nightline" I'm Rebecca Jarvis in Westbury, new York.
This transcript has been automatically generated and may not be 100% accurate.