Credit and debit card skimmers secretly attached to gas pumps are an increasingly common scourge throughout the United States. But the tables can be turned when these fraud devices are discovered, as evidenced by one California police department that has eschewed costly and time-consuming stakeouts in favor of affixing GPS tracking devices to the skimmers and then waiting for thieves to come collect their bounty.

One morning last year the Redlands, Calif. police department received a call about a skimming device that was found attached to a local gas pump. This wasn’t the first call of the day about such a discovery, but Redlands police didn’t exactly have time to stake out the compromised pumps. Instead, they attached a specially-made GPS tracking device to the pump skimmer.

At around 5 a.m. the next morning, a computer screen at the Redlands PD indicated that the compromised skimming device was on the move. The GPS device that the cops had hidden inside the skimmer was beaconing its location every six seconds, and the police were quickly able to determine that the skimmer was heading down a highway adjacent to the gas station and traveling at more than 50 MPH. Using handheld radios to pinpoint the exact location of the tracker, the police were able to locate the suspects, who were caught with several other devices implicating them in an organized crime ring.

This story in October 2014 the U.S. Justice Department‘s “COPS Office” indicates that the Redlands PD has taken the lead in using GPS technology to solve a variety of crimes, and had credited the technology with helping secure at least 139 arrests.

According to 3VR Inc., a San Francisco based surveillance and security firm, the Redlands PD has used the GPS technology to apprehend offender committing armed robberies, vehicle burglary, pharmaceutical burglary and robbery, cell store burglary and robbery, bike theft, laptop theft, constructions site theft, fire hydrant theft, metal theft, wire theft, 3rd row seat theft, cemetery theft, vending machine theft, mail theft, UPS parcel theft, residential burglary, tire theft, vehicle theft, cigarette theft, etc. “The technology has also been used to voluntarily track informants by sewing a unit into a purse,” 3VR wrote in a recent newsletter.

3VR notes that the GPS device used by the Redlands PD in the pump skimmer case runs for about six hours on a full battery, meaning cops have about six hours to locate the device before the GPS stops transmitting. However, the devices can be tweaked to extend the battery life, by allowing them to switch on only in the event the device actually is moved, and by decreasing the frequency with which the device beacons home.

One increasingly common type of gas pump skimmer — those equipped with Bluetooth technology — might not be as susceptible to these kinds of police tricks. Bluetooth skimmers are equipped to tap directly into the pump’s power supply, and to allow thieves to retrieve stolen card data wirelessly, just by pulling up to the compromised pump with a Bluetooth enabled laptop or smartphone and downloading the data without ever leaving the vehicle.

Unlike ATM skimmers, skimming devices attached to gas pumps usually are impossible for the average customer to spot because the skimmers are not stuck to the outside of the machine, but rather hidden inside after thieves gain access to the pump’s insides. I wouldn’t worry too much about pump skimmers, unless you’re accustomed to paying for fuel with a debit card: Having your checking account emptied of cash while your bank sorts out the situation can be a huge hassle and create secondary problems (bounced checks, for instance). Use a credit card instead.

How common are pump skimmers?  Thieves tend to attack multiple filling stations along a major interstate, as detailed in this July 2010 story about pump skimmer scammers. More recently, a law enforcement sweep of 6,100 gas stations in Florida last month turned up skimmers at 81 locations.

If you’re as fascinated by ATM and pump skimmers as I am, check out the rest of my skimmer series, All About Skimmers.