SAN LEANDRO (CBS SF) – Police in San Leandro said they have caught two men suspected of preying on ATM customers.

According to police, Tremell Watts and Blade Kittrell stole money from customers’ bank accounts, in a practice known as “shoulder surfing.”

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Police said they targeted the Bank of America on East 14th Street in San Leandro.

Shoulder surfing involves thieves looking over the shoulders of people withdrawing cash and spying on their PIN numbers. Once the person leaves the ATM, thieves quickly begin a new transaction and pocket the cash.

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Police said tens of thousands of dollars have been stolen since last May and that the problem is not isolated to San Leandro.

“This is a nationwide trend,” said Lt. Robert McManus of the San Leandro Police. “You can walk right up to an ATM machine, you can look over someone’s shoulder, you can quickly take a few hundred dollars.”

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Police say customers should protect themselves by being aware of their surroundings and to report any suspicious activity.