When the FBI searched the Russian Hill apartment of Ryan Kelly Chamberlain II on May 31, they were not looking for components of a bomb.

They had hoped to find lethal toxins Chamberlain allegedly purchased on anonymous websites, part of the “darknet” or “deepweb,” using cybercurrency known as Bitcoin. They were also looking for the computers he used to access those sites.

It does not appear that is what they found, since they charged Chamberlain, who was arrested June 2 after a three-day manhunt and remains in custody, with possessing bomb- making materials.

According to the search warrant, the FBI had been led to his home after a series of tips and arrests because of his alleged use of anonymous sites to purchase abrin and pure nicotine, both lethal toxins.

“The investigation has revealed that Chamberlain has utilized an anonymous, internet-based marketplace known as Black Market Reloaded,” states the unsealed affidavit.

The document states that the FBI expected to find evidence of “hidden services websites such as Silk Road, Bitmail, or Bitcoin payment websites and or systems.”

Such darknet sites have been the subject of federal investigations with links to San Francisco before.

Most recently, Ross William Ulbricht was arrested by FBI agents in a Glen Park library in February and charged with running Silk Road, a site that offered drugs, money laundering, murder-for-hire and other illegal services.

It's unclear what, if any, connection the joint investigation, which involved the FBI, ATF and Homeland Security investigations units, had with previous probes into black market websites.

But the two sites, Black Market Reloaded and Silk Road, do appear similar in terms of how they operate and what they offer.

The investigation found that Black Market Reloaded “provides a sales platform that enables vendors and buyers … to conduct anonymous transactions online involving the sale and a variety of illegal goods.”

Those goods included toxins, chemicals, firearms, biological agents, explosives and narcotics, according to the warrant.

Chamberlain has yet to make a plea in the case. His next court date is scheduled for Monday.

Bay Area NewsCrimeCrime & CourtsRyan Chamberlain Lethal Toxins FBI Silk Road