BOSTON -- Officials are looking for the person who they say kidnapped a postal truck driver, handcuffed him to the steering wheel and stole several bags from the mail truck on Thursday night.

NewsCenter 5's Jack Harper reported that the driver and the truck were found on Ziegler Street, not too far from the Roxbury Post Office. The driver was handcuffed to the steering wheel and screaming for help.

The robber allegedly approached the driver saying he had a weapon. He then told the worker to drive to Ziegler Street. The man then went through the truck.

"The assailant came out of nowhere, seemed to be hiding under the truck, came up to him, made like he had a weapon -- I don't believe any weapon was seen -- forced him to get into the truck, and drive off the postal property," said Bob Cannon, of the Postal Service.

Once they were off the property and on a side street, the man ordered the driver to pull over.

"Took the keys from him, opened up the truck and took at least four pouches out of the truck," Cannon said.

Those bags contained cash receipts from four neighborhood post offices -- Uphams Corner, Mission Hill, Grove Hall and Roxbury.

"Fortunately, it is very infrequent. Unfortunately it does happen but it is rare, certainly of this magnitude, too," Cannon said.

A $50,000 reward is being offered by the postal service. The kidnapping charge could carry a sentence of life in prison.