Federal prosecutors have filed documents that say the deadly poison ricin was found on items dumped by the suspect charged in the investigation of poisoned letters sent to President Barack Obama, a U.S. senator and a Mississippi judge.

An FBI affidavit made public Tuesday says that on April 22, James Everett Dutschke removed several items from his former martial arts studio in Tupelo, Miss.

The affidavit says tests indicated that items, including a dust mask, recovered from a trash can down the street from the studio tested positive for ricin.

The affidavit also says trace amounts of ricin were found in the studio, and that Dutschke bought castor beans on the Internet.

Castor beans are used to make ricin.

(AP)