SAN MATEO (KTVU) -- Local law enforcement officers say they're seeing a growing number of skimming devices and their placement is raising alarm.
That's because the devices, which steal a customer's credit card or ATM data, are now being found in the interior of the gas pump themselves, meaning some scammers now have the ability to go where their access has been restricted in the past.
At a 76 gas station on El Camino Real in San Mateo, unleaded fuel is selling at $2.66 a gallon. Drivers may see savings but thieves see dollar signs. Two skimming devices were found inside the fuel pump.
"It's just a little concerning that they found that on the inside of the machine and that someone is actually able to access the actual device itself," said customer Chris Young.
Police said they believe someone was able to get a universal key, which can sometimes be found online, and managed to break into the pump and plant the card reading device inside the gas pump.
"It happens late at night or on weekends when it's busy so there's less attention from the attendant," said police Sgt. Amanda Von Glahn. "Or it's someone that knows the pump and who is servicing it."
Police said the skimmers found at the gas station could have obtained information from thousands of people, for several weeks before an employee finally noticed it when they serviced the pump.
In some instances, the scammers don't attempt to hide the skimmers and will place them in plain view of users.
Police say consumers should be proactive to avoid being ripped off. That means using apps like Apple Pay or Android Pay or paying with cash.
The general manager at the 76 station said workers removed the devices that were found and updated their software inside the pump to prevent consumer information from being stolen. Station officials also say they hope their surveillance system and its visible cameras will also serve as a deterrent.
By KTVU FOX 2 reporter Alyana Gomez.