The incident happened around 2:00 p.m. at a store inside Ballston Common Mall. Police say Matthew Martin, 45, purchased some DVDs at the store. Before he left, however, a store clerk noticed that he was trying to conceal other items that he did not buy, according to Arlington County Police Department spokesman Dustin Sternbeck.
At that point, police say, Martin displayed a knife, threatened the clerk and fled the scene without paying for the concealed merchandise.