SALT LAKE CITY (AP) - A man possibly sickened by the deadly toxin ricin in Las Vegas is described by former neighbors in Utah and California as a hotheaded child who grew up to be an introverted adult who loved animals.

Roger Von Bergendorff also has been beset by financial problems, filing for bankruptcy in 2000.

Bergendorff, 57, remained hospitalized at Spring Valley Hospital in Las Vegas.

"The patient's condition hasn't changed. It's still critical," hospital spokeswoman Naomi Jones said Monday. Jones said she was prevented from providing more information about the patient's treatment.

Bergendorff has been hospitalized since Feb. 14. Police and FBI have said he's unconscious. Health officials are trying to confirm whether Bergendorff's respiratory ailment stemmed from ricin exposure.

The FBI searched a home in the Salt Lake City suburb of Riverton and three storage units over the weekend, but FBI special agent Juan Becerra would not say Monday what, if anything, had been found. FBI said the search had concluded and there was no health threat discovered at the home or the storage units.

Authorities believed they had recovered all the ricin in several vials found last week from the motel several blocks off the Las Vegas strip where Bergendorff had stayed, but they wanted to also check the home in Riverton, where Bergendorff had lived with his cousin, Tom Tholen, and his family.

Nearby homes were evacuated Sunday as FBI agents in hazardous-material protection suits meticulously searched Tholen's house.

Tholen declined to comment Monday when reached by telephone. He
said he had not spoken with investigators.

Bergendorff had lived in the Riverton house for more than a year before moving to Las Vegas about a year ago, said Tammy Ewell, who lives across the street.

She described him Monday as an introverted man who drove his hosts to their wit's end by living rent-free and taking advantage of their food and computer services.

"He was just a quiet man who wasn't assertive enough to get a job," she said, "to put it kindly."

Bergendorff wasn't social with neighbors and often didn't return a friendly wave, Ewell said. When she and Bergendorff did talk, it was usually about the weather and frequently because he was walking his German shepherd up and down the street.

What Bergendorff lacked in human social graces, he made up for in affinity for animals, she said. She said he returned to Utah several times after he moved to Las Vegas to search for a lost cat.

"We had a few more conversations about how much his cat meant to him, and how he would do anything for this cat," she said.

Tholen contacted motel management Feb. 22 to inform them about pets in the room, and Las Vegas Humane Society officials took custody of a dog and two cats. The dog, which officials said was mortally ill after going at least a week without food or water, was euthanized.

Bergendorff, the middle child of three sons, grew up in the San Diego suburb of La Mesa.

"He used to be a hothead," former neighbor Paul Slade told The San Diego Union-Tribune. "When we played football he'd always be the first to get in a fight. When he got older he kind of calmed down."

Slade attended Grossmont College with Bergendorff.

Bergendorff would move back to the La Mesa house to take care of his mother, Lola, the newspaper said. She died in 2001. Her obituary said Bergendorff lived in Reno at that time. His father, Frederick, died in 1991.

Another neighbor, Steve McNulty, told the Union-Tribune that Bergendorff kept to himself while he was caring for his mother.

Mike Massaglia and his wife, who now own the family home, told the newspaper they bought the house from a bank last year and had not heard of Bergendorff.

Bergendorff declared bankruptcy in San Diego in 2000, court records show. The filing was discharged in about 3.5 months. In 1993, a civil judgment was entered against him for an unpaid auto loan of about $13,000 in Orange County, California.

Public records show Bergendorff used at least six addresses between 1983 and 2007 in cities Utah and California.

As little as 500 micrograms of ricin, an amount about the size of the head of a pin, can kill a human, according to the Centers for Disease Control and Prevention. The only legal use for ricin is cancer research.

Von Roebuck, spokesman for the CDC, said a sample of the substance arrived Monday in Atlanta.

"We're going to look at it to confirm that it is indeed ricin," Roebuck said, adding that the results would be reported to Nevada state officials handling the investigation.

Roebuck said he did not know how long testing would take.

Las Vegas police said that firearms, an "anarchist-type textbook" and castor beans were found in the motel room. The book was tabbed at a spot containing information about ricin.
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Associated Press writer Ken Ritter in Las Vegas contributed to
this report.

(Copyright 2008 by The Associated Press. All Rights Reserved.)