Paul Kevin Curtis in an undated personal photo (Facebook via CBS NEWS)
OXFORD, Miss. (AP) - Investigators say they haven't found any ricin in the house of Mississippi man accused of mailing poisoned letters to President Barack Obama, a U.S. senator and a local judge.
FBI Agent Brandon Grant, testifying in federal court Monday, said a Friday search of Paul Kevin Curtis' house in Corinth, Miss., did not turn up ricin or ingredients for the poison. A search of Curtis' computers has found no evidence so far that he researched making ricin.
Federal investigators believe the letters were mailed by Curtis, an Elvis impersonator who family members say suffers from bipolar disorder.
Through his lawyer, Curtis has denied involvement in letters sent to Obama, Mississippi Republican Sen. Roger Wicker, and a Lee County, Miss., judge.
Curtis' lawyer suggests in court that an enemy may have framed Curtis.