Updated 6/3/12 at 10:16 a.m.

OAK LAWN, Ill. (CBS) —After a standoff that lasted more than 10 hours, police in Oak Lawn and the FBI say they arrested a bank robber – after getting him out of a ceiling air duct.

The division chief of the Oak Lawn Police, Michael Kaufmann, says the bank robber cut through the roof over the bank to get in – and had to go through six inches of concrete.

Kaufmann says it’s likely the robber knew something about the bank – or knew somebody who did.

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And that he started cutting before this weekend.

Kaufmann says the robber dropped down into a secure area of the Bank of America on 111th – tied up two employees – and left through the roof with a duffel bag of cash.

Then Kaufmann says the robber ran to the roof over a nearby office – to hide from police.

“He broke a window to get access to one of the offices, and when he broke the window he cut his hand.”

Kaufmann says police saw the blood – and traced the robber to an air duct. And he says it took some doing to get the robber out.

“In fact, he couldn’t get out and move. He was fortunate (that police were there.) Because if they’d never found him, he could’ve died in there.”

Kaufmann says the bank robber was out and arrested by about 12:30 this morning.

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