CONCORD, NC (WBTV) - Police in Concord are investigating after they say someone sent a white powder substance to the office of a U.S. Congressman. According to police, officers and firefighters were called to the office of U.S. Congressman Richard Hudson around 10:15 a.m. Tuesday morning. Officers say the call was in reference to a white powder substance in a letter that had been opened inside his North Carolina office.