Investigators are stepping up their efforts to find the source of frequent bomb threats to two House of Raeford facilities in Duplin County, N.C.

No bombs have been found, but authorities and the company have taken every bomb threat phone call seriously since they began in June. Officials from the House of Raeford told WCTI 12 (local television news) that when they get a bomb threat the procedure is to evacuate everyone and initiate a full search, which can take 45 minutes to two hours. Captain Stan Jones said they could be losing millions of dollars when they have to shut down the plant to search the building. According to the report, House of Raeford has received as many as four calls in one day.