This is like a reverse bank robbery.

There's a 19-year-old guy named Nathan Newell from Bel Air, Maryland, and he's a bank teller at a Freedom Federal Credit Union branch.

Well . . . he was working last Monday when a 78-year-old guy came in and made a big withdrawal.

So that night, Nathan went to the guy's house . . . forced his way in . . . attacked the guy . . . and robbed him.  He ran off when the guy's 57-year-old stepdaughter pulled a gun and threatened to call the cops.

The police were able to put the pieces together and they arrested Nathan at the bank two days later.

He's been charged with robbery, burglary, assault, and home invasion. 

(Here's his mugshot.)