Dobbs said Tuesday that FBI agents haven't told her anything, including whether the building poses a health threat. Inside the studio is one large room with a smaller reception area and a concrete floor. Police tape covered the front and the small back door.
FBI spokeswoman Deborah Madden said Tuesday that the business, Tupelo Taekwondo Plus, was sealed off after evidence that was collected tested positive for "trace levels of ricin."
"The FBI is now conducting further forensic examination for the purpose of identifying trace evidence, residues and signatures of production that could provide evidence to support the investigation," she said in a news release.
The FBI has not yet revealed details about how lethal the ricin was. A Senate official has said the ricin was not weaponized, meaning it wasn't in a form that could easily enter the body. If inhaled, ricin can cause respiratory failure, among other symptoms. No antidote exists.
An expert at the National Bioforensics Analysis Center in Fort Detrick, Md., said the extraction process employed in this case appears to have been more involved than "merely grinding castor beans," the affidavit said.
The most notable case of ricin poisoning was in 1978, when a Bulgarian dissident was lethally injected with it by an operative of that country's secret service.
Dutschke bought 50 castor beans off eBay in November 2012 and 50 more in December 2012, the affidavit said.
The affidavit had been sealed since it was filed Friday in U.S. District Court in Oxford. It also said that on the evening of Dec. 31, 2012, someone using his "computer downloaded a publication, Standard Operating Procedure for Ricin, which describes safe handling and storage methods for ricin, and approximately two hours later, Immunochromotography Detection of Ricin in Environmental and Biological Samples, which describes a method for detecting ricin."