Over the past two weeks, somebody has pried off locks on collection boxes outside of post offices in the small central Minnesota towns of Vining, Henning, Battle Lake and Hewitt and made off with bills, letters, postcards and parcels. Last week, the mail thief struck again in Big Lake.

Workers in Big Lake discovered the theft on the morning of Feb. 3 when they went to collect mail that had been dropped off overnight. A lock on the back side of the box had been broken and the box's contents removed.

Police and postal officials don't know if the thefts are the work of the same person, or if the cases are related. But "it is a similar M.O.," said U.S. Postal Inspector Jeff Long. "Are they working their way south? It's hard to say."

They are hoping a video surveillance camera from a nearby liquor store that captured the "smash and grab" crime in Big Lake might help. It captured a 4-door, dark blue Ford F-150 pickup, oval body style with the lettering of "FX4" observed along the top side of the truck box driving away from the scene. It also showed one suspect wearing black shoes, dark stretch-style pants and a hoodie, said Big Lake Police Chief, Joel D. Scharf.

Another video associated with a different burglary shows an individual using a stolen gift card, he said.

The postal service is asking anybody who believes they placed mail in those collections boxes that may have been stolen to call U.S. Postal Inspectors at 1-877-876-2455 or file a report on its website, www.postalinspectors.uspis.gov.