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.