LAS VEGAS — An unemployed graphic designer who pleaded guilty to possessing toxic ricin said Friday he distilled the lethal powder in 1998 while living in San Diego from the beans of a backyard castor plant, and carried it with him for a decade while living in Reno, Las Vegas and near Salt Lake City.

"I made it," Roger Bergendorff, 57, told The Associated Press during an exclusive interview from a Las Vegas-area jail, where he is being held pending sentencing.

Police and prosecutors have cast Bergendorff as a troubled man who acted alone, and they have said the case was not linked to terrorism.

Bergendorff, who pleaded guilty Monday to federal possession of a biological toxin and weapons charges, denied any criminal intent and said he never intentionally or accidentally released any of the lethal powder.

"Absolutely not. Zero chance. I had it triple-sealed," Bergendorff said in a series of timed telephone calls he made to the AP from the jail.

Bergendorff also said he was sure ricin did not cause the breathing problems that prompted him to call an ambulance Feb. 14 to his motel room a few blocks off the Las Vegas Strip.

"It was in a container in my safe and it hadn't been touched. There was no reason to touch it," he said.

Authorities suspected Bergendorff was exposed to ricin, but said they could not be sure because the poison breaks down in the body within days. Bergendorff was hospitalized for two weeks before the ricin was discovered in his room.

Bergendorff, who remained in a wheelchair Monday during his appearance in a U.S. District Court, blamed his illness on stress following the death of his older brother. He said he fell unconscious before arriving at a hospital, and didn't remember anything else until he awoke three weeks later from what he described as a coma.

The FBI interviewed him several times, he said, and he told the truth in interviews that preceded his arrest April 16 — the day he was released from a hospital.

He pleaded guilty Monday to two charges that could have each gotten him 10 years in prison and a $250,000 fine. Instead, prosecutors and Bergendorff's lawyer agreed he should receive a sentence of 3 years, 1 month in federal prison.

Prosecutors dropped a third weapons charge stemming from allegations that he possessed illegal silencers for a .22-caliber weapon.

Bergendorff's lawyer, Paul Riddle, said the deal benefited his client because it meant he could be released within three years if he behaves in prison and gets credit for time already served in the North Las Vegas lockup.

Bergendorff's cousin, Thomas Tholen, 54, of Riverton, has pleaded not guilty in federal court in Salt Lake City to one felony count of knowing about a crime but failing to report it. He is due to plea guilty Monday to a lesser felony charge in the case. His defense attorney, Greg Skordas, said he could not disclose the exact terms of the plea deal.

Federal prosecutors allege that Tholen knew Bergendorff had ricin when he lived at Tholen's home in Utah from February 2005 to May 2006. Bergendorff spent several more months living in a camper trailer owned by a Utah neighbor of Tholen's before moving to Las Vegas in September 2006.

Bergendorff said he didn't make ricin in Utah, and couldn't recall after his hospitalization if he ever distilled any while living in Reno from 2001 to 2004.

Tholen said he was trying to help a down-and-out relative when he traveled to Las Vegas and boxed items in Bergendorff's motel room when the rent ran out while Bergendorff was hospitalized.

"All the way through, that's what I've done," Tholen told the AP on Friday. "He was dying. That's what they told me. He was basically living on charity. The church had paid for his living situation. My concern was just to help everybody else.

"Every once in a while, something like this happens," Tholen added. "It backfires and kicks you in the teeth."

Tholen alerted authorities to containers with what police later said was about 4 grams of "crude" but lethal ricin powder. The discovery prompted an evacuation and decontamination process at the motel, and seven people were taken to hospitals for treatment.

Ricin has no antidote and can be lethal in amounts as small as the head of a pin. It prevents the body from synthesizing proteins and shuts down vital organs such as the liver, kidneys and heart

A prosecutor told a federal judge that the powder Tholen gave police Feb. 28 could have killed more than 500 people.

"I was escorted out of Las Vegas, and I haven't been back," said Tholen, who said he was whisked to a hospital, checked for contamination and caught a flight home to Salt Lake City.

"I wasn't actually taken into custody, but they kept a close eye on me right to the airport and out of Las Vegas, so I had no more access to his stuff or his room," Tholen said. "I have no idea at all what the disposition of anything is."