A dust mask and other items seized from the martial arts studio of a Mississippi man charged with sending letters laced with a deadly poison to President Barack Obama have tested positive for ricin, according to a court document released on Tuesday.
Tupelo martial arts instructor Everett Dutschke is also charged with sending poisoned letters to two other public officials.
Records seized by the FBI also showed that he ordered castor bean seeds, used to make ricin, from eBay, FBI Special Agent Stephen Thomason said in an eight-page affidavit.
A Mississippi martial arts instructor has been charged with attempting to use a biological weapon, the US Department of Justice has announced.
James Everett Dutschke, who is 41, was arrested following searches at his home and a former business, as part of an investigation into ricin-laced letters sent to President Barack Obama and two other public officials.
If convicted, Dutschke faces maximum possible penalties of life imprisonment, a $250,000 fine and five years of supervised release.
He is expected to appear in the United States District Court in Oxford, Mississippi, on Monday.
A man has been arrested in connection with three letters sent to US officials, including President Barack Obama, which are suspected of containing poisonous ricin.
The FBI said Paul Kevin Curtis, a 45-year-old from Corinth, Mississippi, is "believed to be responsible for the mailings of the three letters sent through the US Postal Inspection Service."
The letters, "which contained a granular substance that preliminarily tested positive for ricin" were addressed to a Republican senator, the White House and a Mississippi justice official, the FBI said.