The Las Vegas hotel suite where vials of ricin were found Thursday also contained guns and literature about anarchy with information on the deadly toxin, police said Friday.
Nevertheless, Las Vegas police continued to downplay the significance of the ricin discovery, saying they had ruled out terrorism as a motive.
"I want to assure everybody that the Las Vegas Valley is safe," Las Vegas police Capt. Joseph Lombardo said. "We don't currently have any terrorist threat at this time or possibility of contamination (due) to ricin."
The Metropolitan Police Department reported one person has been injured by the biological agent. That man has been in critical condition at Spring Valley Hospital Medical Center for more than two weeks.
Police said the man is 57 years old and was staying in the suite at the Extended Stay America on Valley View Boulevard near Flamingo Road where the ricin was found.
Police have not identified the man, but a Homeland Security internal document obtained by the Review-Journal states that he is Roger Von Bergendorff.
The man placed an emergency call from the suite on Feb. 14, saying he was in respiratory distress and asking to be transported to a hospital, police said.
"He's unable to speak with us right now," said Deputy Chief Kathy Suey, who leads the Police Department's Homeland Security Division.
His medical condition, however, was consistent with exposure to the poisonous substance, authorities said.
If a person exposed to ricin doesn't die within three to five days, the victim usually recovers, according to the Centers for Disease Control and Prevention.
Seven other people, including three police officers and three employees at the long-term stay hotel, also were hospitalized as a precaution. No one other than Von Bergendorff had exhibited signs of ricin exposure.
Before Thursday's discovery of the deadly poison, hotel management and Las Vegas police had visited the suite twice without detecting it.
On Feb. 22, eight days after Von Bergendorff was hospitalized, one of the man's "relations" called hotel management to alert them to two cats and one dog that were in the suite, Lombardo said.
Management contacted the Humane Society to take care of the animals, and the cats were taken in and are in good health. A veterinarian with the society determined the dog was in ill health because of lack of food and water and the animal was destroyed, Lombardo said.
On Tuesday, management at the hotel began eviction procedures and called Las Vegas police after discovering four firearms in the suite, the Homeland Security memo states .
Police then found an anarchist textbook that was "tabbed" to a section on ricin, Lombardo said.
That discovery prompted police investigators to test the room for the deadly substance. The test was negative.
On Thursday, a man who "claimed to be a relative" was in the suite and discovered several vials of ricin in a bag, along with castor beans from which the substance is derived, Suey said.
Police have not identified the man, whom they said was 53 years old. But the Homeland Security document identified him as Thomas Tholen.
Authorities said Tholen took the vials of ricin to the manager's office. It was not clear whether Tholen knew what the vials contained.
Tholen and three other people who were inside the manager's office were taken to Desert Springs Hospital as a precaution.
Police said Tholen stayed at the Excalibur on Wednesday night. Friday evening investigators found the room was not tainted from ricin, Lombardo said.
Police believe that all of the ricin related to the incident has been contained.
Las Vegas police spokesman Bill Cassell said Von Bergendorff "is not considered a criminal suspect."
Lombardo said: "I don't want to make any conclusions with the anarchist-type textbook. It doesn't make you a terrorist because you have this type textbook. It doesn't make you a terrorist if you possess firearms."