RIVERTON, Utah -- FBI agents wearing protective suits searched for the deadly poison ricin at a Utah home where a man possibly sickened by the deadly poison had once lived.

Authorities said they believe they had found all of the ricin in several vials recovered Thursday from a Las Vegas motel where Roger Von Bergendorff had been staying, but they wanted to also check the home in Riverton, outside Salt Lake City.

FBI agent Timothy Fuhrman said authorities are taking all precautions necessary to ensure public safety. Nearby homes were evacuated as FBI agents meticulously searched the home belonging to Von Bergendorff's cousin Thomas Tholan.

Von Bergendorff had been staying in the motel room where the ricin was found and has been hospitalized since Feb. 14. He has been unconscious since his hospitalization, so police and the FBI have not been able to question him about the ricin found in his room.

He was hospitalized about two weeks ago after complaining of breathing problems but it wasn't until a few days ago that the powdered ricin was discovered in the motel room where he had been staying. While he remains in intensive care, one of his cousin's says he's "holding his own."

Health officials are still trying to confirm whether Von Bergendorff's respiratory ailment stemmed from ricin exposure. The FBI got a search warrant for Tholan's home, where Von Bergendorff once lived.

Ricin can be deadly if ingested, inhaled or injected into the body. Authorities said that two-tenths of a milligram is enough to kill a person. It has been used in some cancer research, but it has also been used in assassinations and turned up in the homes of suspected terrorists. Ricin is 6,000 times more toxic than cyanide.

Police, the FBI and Homeland Security officials are trying to piece together how several vials of the poison ended up at the motel several blocks from the Strip.

Officials said they also found firearms and what officials call an "anarchist type textbook" in the room on Friday. However, police insist there is no apparent link to terrorism and public health officials say there's no threat to the public.