A man accused of mailing letters with suspected ricin to President Barack Obama and other officials maintains he is innocent, his attorney has said.
Paul Kevin Curtis, 45, is charged with threatening Obama and others, according to a Thursday news release from the US department of justice. He appeared in federal court on the two charges and if convicted could face up to 15 years in prison.
Curtis was surprised by his arrest and maintains he is innocent, his attorney said after Thursday's hearing.
Curtis "maintains 100 per cent that he did not do this," attorney Christi R. McCoy said. She added that she knows him and his family and that it is hard for her to believe the charges against him.
Curtis is said that he believes he has uncovered a conspiracy to sell human body parts on the black market and claims "various parties within the government" were trying to ruin his reputation.
His attorney said she had not yet decided whether to seek a hearing to determine if Curtis is mentally competent to stand trial.
An FBI affidavit released on Thursday said Curtis sent three letters with suspected ricin to Obama, US Senator Roger Wicker of Mississippi and a Mississippi judge. The letters read:
"No one wanted to listen to me before. There are still 'Missing Pieces.' Maybe I have your attention now even if that means someone must die. This must stop. To see a wrong and not expose it, is to become a silent partner to its continuance. I am KC and I approve this message."
The FBI said there was no indication of a connection between the letters and the Monday bombing in Boston that killed three people and injured more than 170. The letters to Obama and Wicker were postmarked April 8, before the marathon.
The affidavit says Curtis had sent letters to Wicker's office several times before with the message "this is Kevin Curtis and I approve this message." Such language is typically used by candidates at the end of campaign ads.
In several letters to Wicker and other officials, Curtis said he was writing a novel about black market body parts called "Missing Pieces".
Curtis also had posted language similar to the letters on his Facebook page, the affidavit says.
The documents indicate Curtis had been distrustful of the government for years. In 2007, Curtis' ex-wife called police to report that her husband was extremely delusional, anti-government and felt the government was spying on him with drones.
Curtis was arrested on Wednesday at his home.
Local police had not had any contact with him prior to his arrest, Corinth Police Department Captain Ralph Dance told The Associated Press on Thursday.
Dance said the department aided the FBI during the arrest and that Curtis did not resist.
The material discovered in a letter to Wicker has been confirmed through field testing and laboratory testing to contain ricin, Senate Sergeant-at-Arms Terrance Gainer said on Thursday. The FBI has not yet reported the results of its own testing of materials sent to Wicker and to Obama.
Preliminary field tests can often show false positives for ricin. Ricin is derived from the castor plant that makes castor oil. There is no antidote, and it is deadliest when inhaled. The material sent to Wicker was not weaponised, Gainer said.
An FBI intelligence bulletin obtained by the AP news agency said the two letters were postmarked Memphis, Tennessee. Curtis' neighbours said he did not seem violent.
Ricky Curtis, who said he was Kevin Curtis' cousin, said the family was shocked. He described his cousin as a "super entertainer" who impersonated Elvis and numerous other singers.
"I don't think anybody had a clue that this kind of stuff was weighing on his mind," Ricky Curtis said in a telephone interview.