The letters were intercepted April 16 and Dutschke was arrested by federal authorities Saturday. He is to be in court Thursday for a preliminary hearing.
An FBI affidavit filed in U.S. District Court and released Tuesday alleges Dutschke was seen April 22 cleaning out his former business, Tupelo Taekwondo Plus, then tossing several items, including a coffee grinder, a box of latex gloves, a dust mask and an empty bucket of floor adhesive out a window of his vehicle.
The FBI said it recovered the items, and several tests all confirmed the presence of ricin.
Police earlier had arrested Paul Kevin Curtis of Corinth, Miss. He denied sending the letters and accused Dutschke of framing him.
In the seven-page affidavit, Special Agent Stephen Thomason states the letters sent Obama, Wicker and Holland each contained language apparently intended to draw authorities' attention to Curtis.
The affidavit states Curtis and Dutschke "have known each other for several years and have had a contentious personal relationship which has manifested itself in email traffic and social media postings."
The FBI said its agents also interviewed a witness who said Dutschke had said years ago he could manufacture a deadly "poison" he could place in envelopes and send to elected officials.
The document states Dutschke once had a civil case dismissed by Holland and lost a state legislative race to her son in 2007.
The document also revealed Dutschke was arrested in January on state charges, and his laptop computer and several flash drives were seized.
A search of them showed someone had downloaded a publication, "Standard Operating Procedure for Ricin."
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