BOSTON (AP) -- In what could be major break in the Boston Marathon case, investigators are on the hunt for a man seen in a department store surveillance video dropping off a bag at the site of the bombings, a local politician said Wednesday. Separately, a law enforcement official confirmed that authorities have found an image of a potential suspect but don't know his name. The development - less than 48 hours after the attack, which left three people dead and more than 170 wounded - marked a possible turning point in a case that has investigators analyzing photos and...