Charges were dropped Tuesday against a Mississippi man accused of sending letters containing the deadly poison ricin.
Paul Curtis had been charged with sending the letters to President Barack Obama and a Mississippi senator, but an FBI agent testified this week that no ricin was found at Curtis' home.
Meanwhile, a package at a Washington military base tested positive for the poison.
Senate Majority Leader Harry Reid said the package was sent to the military mail sorting facility at Bolling Air Force Base.
It's unclear who, if anyone, it was intended for.