CNN EarlyStart May 31, 2013 10:07:00
Expected this investigation to land on their front doorsteps here, but throughout the night we've seen two fbi agents staked out at the house you see behind me. law enforcement officials are questioning a man at this new boston, texas, home, about threatening letters believed to have contained ricin, sent to president obama, new york city michael bloomberg, and a gun control group. >> it kind of hits home a little bit more when it could be someone right down the street. >> reporter: the three suspicious letters were postmarked in shreveport, louisiana. the one addressed to president obama and ...