Sheriff John Anderson said all of the victims used the same gas station in the Madera Ranchos during a 12-day period.
And just this week, they're noticing their accounts are missing money. Investigators said the gas pumps are where dozens credit and debit cards were skimmed.
The information from the cards was stolen by a device hidden inside the card readers.
"Both of our cards were used, both of our cards had to be cancelled. We just got our money back today in our account. It was about $300 that was taken out of our account," said Madera Ranchos resident Leslie Alesi.
Alesi said she and her husband pumped gas at this shell station on Avenue 12 and Road 37 in the Madera Ranchos Labor Day weekend.
Alesi's bank called her Saturday to say their money was being spent in southern California. "They have access now to all my information," she said. "It's an invasion of my privacy, and invasion of my account. It makes me nervous that anyone can get your information that way."
Sheriff Anderson said the skimmers were used between August 30 and September 10th. Now his detectives are trailing the thieves.
"We've been able to track down some of the purchases they've made. They're buying high dollar items in the Los Angeles area," Sheriff Anderson said.
With the information stolen from the card skimmers, like social security, account numbers and addresses the crooks are likely to open up fraudulent credit cards and bank accounts, according to the Sheriff.
"I work my butt off for my money, I don't like that people want to take it for free and go spend it, and I have to work to get it back," Joshua Bailey, another victim.
Bailey also had his account info stolen at the pump. Now he's waiting for new bank cards. The sheriff fears more than 50 people are facing the same financial frustration.
The sheriff said those skimmers could be installed at any gas station or any ATM anywhere. In fact, he told Action News similar incidents have happened at gas stations in Tulare and Fresno.
It's difficult to know whether a skimmer is in place, but experts warn if something about the card reader looks odd don't use it.