An employee of a West Palm Beach, Fla., Best Buy store may have stolen payment card information from approximately 4,000 customers, Best Buy Co. Inc. says in announcement on its Web site. Minneapolis-based Best Buy says the employee, who has since been fired, used an "unauthorized personal device" to capture the card data during November and December. Best Buy says it learned of the theft on Jan. 5. After identifying the employee, the U.S. Secret Service arrested her on Jan. 7. Best Buy says the employee's actions compromised none of its electronic payment systems. According to an affidavit filed by a Secret Service agent, someone former Best Buy employee Brittany Johnson knew as "Alex" approached her in November and offered her a skimming device to place near her cash register to use to capture information off of card magnetic stripes. Johnson, who was offered $17 per card number, was indicted on an access-device fraud charge, the affidavit says. A separate criminal complaint names Marius Harden as the buyer of the stolen credit card data. Harden used the stolen card information to encode blank cards to make fraudulent purchases, the complaint alleges. Harden also intended to sell the stolen card data, asking $500 for 30 card numbers in one instance, according to the affidavit. As of Jan. 31, the Secret Service estimated the total fraud loss at more than $33,000.