Dallas police are continuing their investigation into a new kind of financial crime at the gas pump -- a group of crooks accessing customers’ pin-numbers via Bluetooth technology.
Police recently found five wireless skimmers at four Exxon stations a few miles apart in North Dallas.
At this point, detectives don't know how many victims there are, or precisely how much money has been stolen.
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"They’re using Bluetooth technology, and this is the scary part, to transmit the data. So that means the suspect doesn’t have to go into the pump to retrieve the information they’re looking for,” said Lt Tony Crawford, who heads up Dallas Police's Financial Investigations Unit.
"What makes it so unique is the Bluetooth capabilities, so the suspect can sit in the parking lot right there and as people are swiping their information they're getting all the information."
Police this summer recovered the skimmers from gas stations on Forest Lane, Campbell Road, Preston Road and Hillcrest Avenue.
"They’re not visible from the outside of the gas pump, and they appear to have been made from the same person or same group," Crawford said.
In a statement, an Exxon spokeswoman wrote:
"ExxonMobil does not own or operate Exxon - or Mobil-branded service stations in the United States....Our independent distributors take a number of precautionary measures to prevent skimming, such as inspecting pumps daily for potential signs of tampering."
Exxon spokesman Ashley Alemayehu said the impacted stores are owned by 7-Eleven, and she couldn’t speak to additional security precautions.
Lt. Crawford said until the criminals are caught, all gas stations city-wide should consider extra precautions, like more regular inspections and so-called “tamper tape.”
"When we found these [skimmers] we found them from when the gas pump was having a regular routine inspection, so we don’t know how long they’ve been there," Crawford said. "So we’re asking businesses to regularly check their gas pumps and put tamper seals on their pumps."
He also asked that gas station customers consider changing their habits.
"What [the crooks] are preying on is our convenience, that we simply stand outside and pay right at the gas pump. So we ask that you pay inside," he said.
Cybersecurity experts said it may be good advice, but in this day and age, many drivers aren't likely to follow it.
"But that's sort of going backwards, right? It's sort of like saying let's go back to 1960. Where everything was cash and the term debit card wasn't around," said Bhavani Thuraisingham, Professor of Computer Sciences at UT Dallas, and a cybersecurity expert.
She says companies need to address the growing vulnerability of micro-processors to hackers.
"Almost everyone has chips in their cards now, and they have to put the credit cards in the machine at the store and leave them there, she said. "Whenever you have a micro-processor, there is a potential for vulnerability because there is both hardware and software on it. There is some malicious code they could have exploited."
The Dallas Police Financial Crimes Unit says their investigation is ongoing. They haven't been able to retrieve any fingerprints from the skimmers.
Many customers still aren't changing their habits from card to cash.
"I'm still going to my your debit card. Just because it's convenient. I hardly ever have cash on me, to be honest, and that's how it is," said gas customer Teresa Crosser, filling up in North Dallas.
Fort Worth Police told NBC5 detectives are aware of what's going on in Dallas, and monitoring the investigation.
A FWPD spokesman said there's been four reports in recent weeks of credit-card skimmers being used at gas stations, but there's no indication Bluetooth technology was used to wirelessly steal personal identity numbers (PIN).