Investigators say at least 65 cases of identity theft from "skimming" may be related.
The East Texas Identity Theft Task Force said that most of incidents occurred at convenience stores.
"A skimmer goes over the mechanism where you insert your credit card... When it goes through he skimmer, it records the information that is on your magnetic strip," Lewisville police Capt. Kevin Deaver said.
Lewisville police are looking into 30 incidents totaling at least $13,000. Police in The Colony report at least 53 cases totaling $10,000.
Deaver said most skimmers have a small camera that records people when they enter their PIN.
"The places where these skimmers are located are generally victims as well," Deaver said. "They don't know that the skimmers are out there or that they are being put on their machines."
Skimmers are commonly placed on gas pumps and can be hard to detect.
"Part of the reason is because the gas pumps don't have cameras on them," Deaver said. "The only way that one would be caught installing one of those would be through the store security system."
Authorities suggest people use a credit card when paying at the pump.
"With the debit part, you have to enter your PIN number, and that's what these people are after," Deaver said.
Police recommend covering your hand if you do have to enter a PIN.