"It's a crime to know about it, do nothing about it and conceal it," prosecutor John Huber said. "There was a several-day period when lawmen were put off the trail."

Tholen, 54, of Riverton, Utah, pleaded not guilty to a felony count of knowing about a crime but failing to report it. If convicted, he could get up to three years in prison and a $250,000 fine, Huber said.

Tholen's cousin, Roger Bergendorff, is charged in Las Vegas with possessing a biological toxin. He was in a hospital for two months after authorities suspect he was poisoned by ricin.

Two weeks after his cousin was admitted to the hospital in February, Tholen went to get Bergendorff's things from a motel room where he had been staying. Tholen found vials containing about 4 grams of "crude" powdered ricin. He gave the vials to the motel manager, who turned them over to authorities.

Huber said Tholen later gave FBI agents "considerable information."

Tholen's attorney Greg Skordas said authorities charged Tholen because they felt he was initially "holding back" information. Skordas maintained that Tholen was as "honest, truthful and forthcoming" as could be, and that he invited authorities to search his house.

"This is a man who never had a brush with the law," Skordas said. "Now he's charged with a felony."

Magistrate Paul Warner set a trial date for July 7. Tholen was released without bail.

Huber said Bergendorff is accused of making the ricin at Tholen's house, although no ricin was found there. A search warrant said traces of ricin were found inside a storage locker rented by Bergendorff where authorities confiscated lab equipment.

The only legal use for ricin is cancer research. An amount of the toxin no larger than the head of a pin could kill a person.

Tholen, a freelance artist who creates characters for video games, told investigators that he kicked Bergendorff out of his house after 15 months in April 2006 because he feared for his safety. He said Bergendorff was making ricin at the same time he was expressing anger at people he believed had wronged him, according to court papers.

Tholen didn't report Bergendorff's activities, even after Bergendorff moved out, because both men had weapons and explosive devices in the basement and the storage unit, according to an FBI affidavit.

In Tholen's house, authorities seized blasting caps, military flares, smoke grenades, demolition fuses, a kitchen grinder and a bag of marbles, according to the search warrant that was unsealed Tuesday. There was no explanation for any of the items.

"It had nothing to do with ricin production," Skordas said outside the court. "And a lot of that stuff is 30 or 40 years old."

Bergendorff, a 57-year-old unemployed graphic artist, told a judge at his April 16 arraignment in Las Vegas that he is no criminal and that he believed he was incapable of ever deploying the deadly poison.

Bergendorff remains jailed in North Las Vegas. His lawyer said he intends to plead not guilty Friday to federal charges of possession of a biological toxin, possession of unregistered firearms and possession of firearms not identified by serial number.

The charges carry a maximum sentence of 30 years in prison and a $750,000 fine.