U.S. investigators say a suspect in Mississippi has been arrested in connection with a poisoned letter sent to U.S. President Barack Obama.
The FBI said suspect Paul Kevin Curtis was arrested Wednesday in Corinth, Mississippi. Investigators did not provide further details.
However, an FBI intelligence bulletin seen by reporters said the suspect April 8 letter to Obama and a second one addressed to U.S. Senator Roger Wicker were postmarked in Memphis, Tennessee and contained some identical wording.
Both letters preliminarily tested positive for ricin, a highly poisonous chemical compound that is deadly in amounts as small as a grain of salt.
Investigators said both letters were intercepted at mail screening facilities away from the White House and Senate offices and consequently did not place either the president or the senator in immediate danger.
Ricin previously turned up in the U.S. Senate mailroom in 2004, forcing authorities to temporarily shut down two Senate office buildings.
Mail laced with the highly toxic bacterium anthrax appeared in post offices, newsrooms and U.S. congressional offices in the days and weeks following the September 11, 2001 terror attacks on New York and Washington.
Those attacks were later linked to a government scientist who killed himself while under investigation in 2008.