LAKE WORTH, Fla. (CBS12) – The U.S. Postal Service (USPS) wants to know who held up one of its letter carriers and is paying big bucks to track him down. On Wednesday, the Postal Service announced a six-digit reward to find the person responsible for the July 12 armed robbery. It explained the letter carrier was robbed between 3:15 p.m. and 3:45 p.m., at a Lake Worth apartment complex on Via Vermilya Road, across the street from the Lantana Airport.