US arrests ricin suspect

The US Justice Department confirmed Wednesday that FBI agents had arrested the 45-year-old suspect at his home in Corinth, Mississippi.

"Today at approximately 5.15 p.m. [2215 UTC], FBI special agents arrested Paul Kevin Curtis," the Justice Department said. He was identified as "the individual believed to be responsible" for the mailings of the letters which were sent through the US Postal Service

The arrest comes hours after the US Secret Service said it had discovered a letter addressed to President Obama that tested positive for the poison ricin. It was reportedly found on Tuesday, the same day a similar letter was posted to Mississippi Senator Roger Wicker was identified.

Media reports suggest that both letters had been signed "I am KC and I approve this message." The wording appeared to emulate the phrase used by political candidates at the end of campaign adverts.

Tensions have been high across the US since the bombings on Monday at the Boston Marathon, when three people were killed and more than 170 injured. The FBI on Wednesday said there were no indications of a link between the letters and the bombing.

All mail to the US Senate has reportedly now been stopped and the Senate mail facility closed while the investigation is underway. Congressional mail has been screened off-site since letters laced with anthrax were sent to Capitol Hill in the wake of the Sept. 11, 2001, attacks on the Pentagon and World Trade Center.

Ricin can prove lethal, even in small quantities, when ingested orally. The poison, found naturally in castor beans, can cause respiratory problems when inhaled.

ccp/jm (AP, Reuters)