(CNN) -- A man believed to have been exposed to the deadly poison ricin in a hotel room in Las Vegas, Nevada, is out of his coma and is being questioned by authorities, FBI Special Agent David Staretz said Friday.
Ricin, guns and an "anarchist-type textbook" were found in a room in this Las Vegas hotel, police say.
Staretz would not comment further on Roger Bergendorff, 57, who authorities said was taken to a hospital February 14 after complaining of breathing difficulties.
He is listed in critical condition, said Naomi Jones, spokeswoman for Spring Valley Hospital Medical Center in Las Vegas.
Bergendorff, an artist who neighbors said had lived in his cousin's basement before moving to Las Vegas, was exposed to the poison in a Las Vegas extended-stay hotel, a law enforcement official said.
The Riverton, Utah, home where Bergendorff previously lived belongs to Thomas Tholen, who along with his wife and daughter tested negative for ricin, according to authorities. That home and three storage areas in nearby West Jordan, Utah, were searched for ricin earlier this month and declared safe by authorities.
A relative who went to Bergendorff's hotel room after he was sent to the hospital found the substance and alerted police February 27.
Ricin is a poison that can be made from waste left over after processing castor beans, according to the Centers for Disease Control and Prevention. It can come in the form of a mist or pellet and can be dissolved in water or weak acid, the agency said. E-mail to a friend