The envelope, addressed to the White House and intercepted at an off-site facility has tested positive for poison ricin, the FBI said Wednesday.
It was immediately quarantined by US Secret Service personnel and a coordinated investigation with the FBI was initiated.
The FBI said White House operations were not affected.
The letter was intercepted Tuesday, the same day that a letter to US Senator Roger Wicker was intercepted at an off-site facility and tested positive for ricin.
Lawmakers on the Capitol Hill confirmed that the Capitol Police intercepted a suspicious letter, which was addressed to Wicker, at an off-site postal screening centre Tuesday morning.
Tags : Barack Obama , US President , Suspicious Letter
