An unemployed graphic designer was sentenced Monday to three and one-half years in federal prison for possessing enough of the deadly toxin ricin to kill hundreds of people.

Roger Bergendorff said in a lengthy speech during his sentencing in Las Vegas that he never intended to hurt anyone.

"I know it sounds crazy. I made it just to have — and that's why I kept it," he said.

Bergendorff detailed a life of personal torment and grief before he was sentenced, but said he never was motivated to use the deadly poison.

"I fear God's judgment," he said before asking for the court's mercy.

U.S. District Court Judge Robert C. Jones told Bergendorff that he needed to understand the severity of crime as he imposed a sentence five months longer than what prosecutors recommended.

"You not only proved a material threat to yourself, you proved a material threat to everyone around you when you possessed this stuff," said Jones, who also ordered a $7,500 fine, which he said was designed to force Bergendorff into a work release program.

The sentencing brought an end to a dramatic saga that raised fears Bergendorff had poisoned himself while plotting a biological attack on tourists or unsuspecting gamblers in Las Vegas, home to nearly 138,000 hotel rooms.

Authorities have since characterized the 57-year-old Bergendorff as a troubled man, but not a terrorist. He pleaded guilty to possession of a biological toxin and possession of unregistered handgun silencers in an Aug. 4 plea deal that avoided trial.

Federal prosecutor Gregory Damm told a federal judge in April that he believed Bergendorff had enough ricin powder to kill more than 500 people.

A charge of possession of firearms without serial numbers was dropped. Bergendorff could have faced up to 30 years in prison and $750,000 in fines if convicted of all charges against him.

U.S. Attorney Gregory Brower said he was satisfied with the sentence imposed and that Bergendorff had effectively waived his right to an appeal under the plea agreement.

Bergendorff's attorney, Paul Riddle, asked that Bergendorff be sent to a federal prison in southern California so he could be near family. The judge granted the request.

Bergendorff said years of grief over dead family members, substance abuse problems and lost girlfriends led him to develop the toxin, which he considered a "harmless outlet for my anger" at the time.

"I really didn't think God had it out for me, but it felt that way," he said.

Police said they also found three handguns and a rifle in the extended-stay motel room where Bergendorff lived with his dog and two cats a few blocks off the Las Vegas Strip, along with castor beans and books with instructions about how to manufacture ricin.

In interviews with The Associated Press, Bergendorff has admitted distilling the lethal powder from the beans of a backyard castor plant while he lived in San Diego in 1998. He said he carried it with him for a decade while living in Reno, in Utah and in Las Vegas.

He has been steadfast that he would never have released it, accidentally or on purpose.

"Absolutely not. Zero chance. I had it triple-sealed," he said during one of a series of telephone calls to the AP from jail days after his guilty plea.

Cancer research is the only legal use for ricin, which has no antidote and can be lethal in amounts the size of the head of a pin.

Bergendorff, whose middle name is Von, also insisted that ricin did not cause the breathing problems that led to his hospitalization Feb. 14. Authorities suspected Bergendorff was exposed to ricin, but said they couldn't be sure because the poison breaks down in the body within days.

Bergendorff said he was overcome after a brother's death in January.

"The stress of his death and his illness caused my illness," Bergendorff said Monday.

He was unconscious in a hospital when his rent ran out and his cousin, Thomas Tholen of Riverton, Utah, traveled to Las Vegas to remove personal items from Bergendorff's motel room.

Tholen alerted authorities to bags of what police later said was about 4 grams of crude but lethal ricin powder. The Feb. 28 discovery prompted an evacuation and decontamination at the motel, and seven people were taken to hospitals for treatment. No serious injuries were reported.

Bergendorff spent nearly four weeks unconscious and several more weeks in critical condition on kidney dialysis. He made previous court appearances in a wheelchair, but walked into the courtroom bound by chains Monday without any aid.

Tholen, 54, was sentenced Oct. 22 to two years probation after pleading guilty Aug. 11 to one federal charge of knowing about a crime but failing to report it.

Federal prosecutors alleged Tholen knew Bergendorff had ricin when he lived at Tholen's house in the Salt Lake City suburbs in 2005-06.