Everett Dutschke stands in the street near his home in Tupelo, Miss., on April 23. (Thomas Wells/AP)

Federal investigators found ricin on a dust mask discarded by the man suspected of sending ricin-laced letters to President Obama and other public officials, according to an FBI affidavit released by a federal court judge on Tuesday.

J. Everett Dutschke, 41, of Tupelo, was under FBI surveillance on April 22 when he returned to the taekwondo studio he once ran and removed several items, placed them in his van and then discarded them in a public garbage receptacle about 100 yards away, the eight-page affidavit said. The items included a coffee grinder, a box of latex gloves and a dust mask. The mask later tested positive for ricin, the affidavit said.

“Based on my training and experience, I know that a coffee bean grinder could be utilized in the process of extracting ricin from castor beans,” Special Agent Stephen E. Thomason wrote in the affidavit. “Furthermore, latex gloves and a dust mask could be utilized as personal protective equipment while the castor beans are being crushed to protect the producer from an accidental exposure.”

More traces of ricin were found in a subsequent search of Dutschke’s former martial arts studio, including on several swabs taken by investigators and in liquid in a drain, the affidavit said.

Dutschke was arrested Saturday at his home and is being held without bail. A preliminary hearing is scheduled for Thursday in federal court.

He pleaded not guilty on Tuesday and told reporters before his arrest that he was not involved in the ricin mailings.

On the same day that he was seen dumping the equipment near his former studio, FBI officials also found a dust mask, yellow paper and address labels similar to those used in the ricin-laced letters in garbage collected at Dutschke’s home in Tupelo.

The next day, agents obtained records that showed Dutschke had ordered 50 red castor bean seeds on eBay and paid for them using PayPal on Nov. 17, 2012. He made a second purchase of 50 red castor bean seeds “on or about” Dec. 1, 2012, the affidavit said.

U.S. Postal Service records confirmed that the second order was delivered to Dutschke’s home four days later, the affidavit said.

“I understand that the number of castor beans ordered is more than sufficient to extract the quantity of ricin found in the three letters,” Thomason wrote.

A search of Dutschke’s home computer also revealed that on Dec. 31, 2012, the following publications were downloaded: “Standard Operating Procedure for Ricin,” which describes safe-
handling and storage methods for ricin, and “Immunochromotography Detection of Ricin in Environmental and Biological Samples,” which describes a method for detecting ricin.

On April 19, two days after they had initially arrested 45-year-old Paul Kevin Curtis in the ricin investigation, law enforcement agents interviewed an unidentified witness who told them that Dutschke had said he knew how to manufacture “poison” and had talked about placing it in envelopes and sending them to public officials.

Curtis’s attorneys said this and other information in the affidavit show that federal officials kept their client incarcerated for days even after gaining strong evidence that Dutschke might be to blame for the letters.

Hal Neilson said he and attorney Christi McCoy “are appalled to discover the prosecutors knew as early as last Friday that Kevin Curtis was not, in any way, involved in the ricin threats.” Charges were dropped, and Curtis was released April 23.

Curtis has accused Dutschke of framing him, an allegation that Dutschke denies.

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