Ryan Chamberlain faces up to 10 years in prison under the terms of a plea arrangement with federal prosecutors, who had originally accused the former political consultant of bomb-making and other charges punishable by life in prison.
Chamberlain, 44, was arrested in June 2014 after an extensive citywide search following the discovery by FBI agents of bomb-making materials and toxic substances in his Polk Street apartment. He has been held without bail but asked last year for supervised releases to seek psychiatric treatment.
Chamberlain had been scheduled to go on trial Tuesday, according to the San Francisco Chronicle newspaper.
But in an agreement reached last week, prosecutors withdrew the most-serious charges and allowed Chamberlain to plead guilty to possession of the biological toxin abrin and possession of a handgun with the serial number removed
Chamberlain also agreed to give up destructive devices and poisons found in his apartment.
Sentencing is scheduled for April 12 before U.S. District Judge Vince Chhabria in San Francisco.
Chamberlain was well-known around local political campaigns and consulted with several of them.
His illegal activities were discovered during the FBI’s investigation of Silk Road black market internet site and a successor, Black Market Reloaded, where users allegedly sold drugs and guns.
