(CNN) -- A federal grand jury indicted a man arrested last week in connection with a mysterious case of exposure to the deadly biological agent ricin, prosecutors said.



Authorities found ricin, weapons and an anarchist manual in Roger Von Bergendorff's Nevada hotel room.



Roger Von Bergendorff, 57, was indicted on charges of possession of a biological toxin, possession of unregistered firearms and possession of firearms not identified by serial number, said Natalie Collins, a spokeswoman for the U.S. attorney's office in Las Vegas, Nevada.



Bergendorff was hospitalized for two months with suspected ricin poisoning, and was discharged before his arrest.



His initial court appearance was last week, Collins said, and he did not enter a plea. An arraignment is scheduled for May 2.



Bergendorff was hospitalized in February complaining of breathing difficulties. Two weeks later, Thomas Tholen, a cousin who went to Bergendorff's Las Vegas hotel room to recover his belongings, discovered what turned out to be ricin.



Authorities also said a search of the room found four guns, the book "Anarchist's Cookbook," a collection of instructions on poisons and other dangerous recipes and castor beans, syringes and beakers. Ricin is extracted from ground-up castor beans.



Tholen was charged earlier in April with failing to report the commission of a crime. A federal grand jury indicted him for allegedly concealing the knowledge that production and possession of a biological agent -- a felony -- was being committed.



Bergendorff previously lived in Tholen's home in Riverton, Utah, just south of Salt Lake City. After the ricin was discovered, the FBI searched that home as well as storage units Bergendorff used in Utah.



Authorities said FBI agents searching the storage units found castor beans, chemicals used in the production of ricin, a respirator, filters, laboratory glassware, syringes and a notebook on ricin production.



If convicted as charged, Bergendorff would face a sentence of up to 30 years in prison. E-mail to a friend
Who was indicted on ricin possession charges? What did authorities find in Bergendorff's Nevada hotel room? Who got indicted? Who has been hospitalized? Where did authorities find ricin and guns?
Roger Von Bergendorff, ricin, weapons and an anarchist manual Roger Von Bergendorff, Roger Von Bergendorff, Roger Von Bergendorff's Nevada hotel room.
question: Who was indicted on ricin possession charges?, answer: Roger Von Bergendorff, | question: What did authorities find in Bergendorff's Nevada hotel room?, answer: ricin, weapons and an anarchist manual | question: Who got indicted?, answer: Roger Von Bergendorff, | question: Who has been hospitalized?, answer: Roger Von Bergendorff, | question: Where did authorities find ricin and guns?, answer: Roger Von Bergendorff's Nevada hotel room.