Police say a Mississippi man has been arrested suspected of sending ricin-spiked letters to President Barack Obama and a US Senator.

Police say the man was taken into custody in Tupelo, Mississippi - the hometown of Senator Roger Wicker, who was the target of the second letter.

Both letters were intercepted at mail sorting facilities away from the US Capitol building and the White House.

The letters to Mr Wicker and Mr Obama were postmarked in Memphis, Tennessee, on April 8.

The Federal Bureau of Investigation said both say: "To see a wrong and not expose it, is to become a silent partner to its continuance." They are signed: "I am KC and I approve this message."

Not long after the envelopes were found, the FBI said it was pursuing leads in tracking down the sender.

 Earlier, Senator Claire McCaskill claimed authorities have a suspect in mind for the Wicker case, but no one has been charged.

Their discovery sparked panic throughout Washington and beyond, with several other "suspicious" envelopes and packages creating security scares on Wednesday. Some were declared harmless, while others were still being investigated.

Senator Carl Levin said a worker at his regional office in Saginaw, Michigan, had received a suspicious letter.

He said: "The letter was not opened, and the staffer followed the proper protocols for the situation, including alerting the authorities, who are now investigating.

"We do not know yet if the mail presented a threat. I'm grateful for my staff's quick response and for government personnel at all levels who are responding."

 Tensions have been high in Washington and across the US since the deadly bombings on Monday at the Boston Marathon that killed three people and injured more than 170.

The FBI said there was no indication of a connection to the marathon attacks. Source foxnews

Pic