WASHINGTON (AP) - The FBI says laboratory tests have confirmed the presence of ricin in letters mailed to a U.S. senator and to President Barack Obama.
The FBI said Thursday that further tests are still being done, but that lab results show the toxin was used in the mailings.
There are no known illnesses from the exposure.
Paul Kevin Curtis, of Corinth, Miss., is suspected of sending the letters to Obama and U.S. Sen. Roger Wicker. He appeared in federal court Thursday on charges of threatening Obama and others, but he did not enter a plea.
His attorney said that the arrest was surprising and that Curtis maintains that he's innocent.
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