It took hours for officials at a downtown Washington bank to realize they’d been robbed.

Police said a man impersonating an armored car guard walked out of a Wachovia bank branch on Pennsylvania Avenue Thursday with more than $100,000, after officials let him sign for a locked bag of cash.

About an hour after the robbery, a real Brinks guard arrived at the bank and was told that another guard had completed the day’s cash pickup.

Police said the Brinks driver waited until he returned to his office to tell his supervisors about the failed pickup. Brinks officials contacted the bank, and a branch manager called D.C. police about 8 p.m. — almost 11 hours after the theft.

Update: Washington Post – 1/12/08:

To the annals of creative bank heists add this: Two Washington area banks turned over more than $850,000 in less than 24 hours this week to someone who impersonated a cash courier and claimed to be filling in for the regular guys.

Thanks to Dickmnixon for letting me know this story was updated. This bank robber (assuming he’s working alone) has had over a day head start with nearly a million in cold hard cash. If he gets caught in the US he’s an idiot.

Update: Well, the robbers are idiots. They all got caught!