Two of them:

On Wednesday, a man dressed as an armored truck employee with the company AT Systems walked into a BB&T bank in Wheaton about 11 a.m., was handed more than $500,000 in cash and walked out, a source familiar with the case said.

It wasn’t until the actual AT Systems employees arrived at the bank, at 11501 Georgia Ave., the next day that bank officials realized they’d been had.

[…]

And on Thursday, about 9:30 a.m., a man dressed as an employee of the security company Brink’s walked into a Wachovia branch in downtown Washington and walked out with more than $350,000.

The man had a badge and a gun holster on his belt, said Debbie Weierman, a spokeswoman for the FBI’s Washington field office. He told officials at the bank, at 801 Pennsylvania Ave. NW, that he was filling in for the regular courier.

About 4 p.m., when the real guard showed up, a bank official told him that someone had picked up the cash, D.C. police said. The guard returned to his office and told a supervisor that he did not make the pickup at the bank. The supervisor called a Wachovia manager, who in turn notified authorities. Police were called nearly 11 hours after the heist.