NOW With Alex Wagner 05/30/13

Letter mailed to Pres. Obama tested positive for ricin

WNBC Chief Investigative Reporter Jonathan Dienst reports that letters sent to President Obama, New York City Mayor Michael Bloomberg, and a gun control lobbyist all tested positive for ricin in preliminary testing. Investigators believe the letters were sent by the same person and that no one has been harmed. ... more Duration: {{video.duration.momentjs}}