The focus of the FBI's investigation into vials of suspected ricin found in a Las Vegas motel room has shifted to Utah.

The FBI on Monday said agents continue to work leads in the case involving Roger Von Bergendorff, who remains comatose in a Nevada hospital with symptoms similar to ricin poisoning.

"The questions we have (are): Was it produced here? What are the hazards here? Where do we go from here? Are there others here who know about it?" FBI Special Agent Juan Becerra told the Deseret Morning News on Monday.

The FBI's investigation has been focused in three parts: determining any public health threat from the deadly toxin; learning about Bergendorff's life (agents said Monday that Von is his middle name); and continuing a criminal probe into the deadly toxin.

The FBI would not comment on the outcome of its searches at the Riverton home of Bergendorff's cousin, where he lived for a short time, and three West Jordan storage units rented by the man.

"There is no threat to public safety at any of those sites," Becerra said. "There is no public safety threat there whatsoever."

Federal agents and emergency responders spent all day Sunday searching the home of Bergendorff's cousin, Tom Tholen. Dressed in protective gear, they went through the home but declined to say what, if anything, they took from there or the storage units. A federal search warrant has been filed under seal, and authorities would not rule out future searches.

Bergendorff, 57, lived with Tholen and his family until recently. He also lived in a nearby camper trailer, neighbors said. He moved to Las Vegas and was staying at an extended-stay motel when he fell ill on Feb. 14.

Inside his room, Las Vegas police said guns, an "anarchist-type" textbook tabbed at a page on ricin and castor beans — from which ricin is made — were found.

Tholen found the vials of ricin in the room and took them to the motel office, triggering a massive emergency response. Six people were decontaminated there. Tholen's wife and daughter were decontaminated when they arrived home on Saturday to find federal authorities and emergency responders camped outside their home.

None have tested positive for ricin exposure.

The FBI said Monday that the Tholen family continues to cooperate with authorities.

"The Tholen family would like to express their appreciation for the many prayers and expressions of concern from our many friends and members of this great community," they said in a statement released late Sunday by a family friend. "THANK YOU!"

The FBI said it wants to know more about Bergendorff, but declined to say if he is a suspect in their investigation. He lived in California and in Utah. Neighbors here have described him as distant, refusing to return a friendly wave, but very concerned about his dog and two cats.

Federal authorities have said they have no indications of any connection in this case to terrorism.

Ricin is deadly in miniscule portions. The Centers for Disease Control and Prevention said as little as 500 micrograms — about the size of the head of a pin — is lethal. It can kill within three to five days. Ricin poison symptoms are flu-like, with difficulty breathing if it's inhaled, or diarrhea and vomiting if it's ingested.

The CDC said Monday it would be testing a sample from the vials to conclusively say it is ricin. A preliminary test at a Nevada laboratory tested positive for ricin, federal authorities said.

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