SAN FRANCISCO (AP) - A search of a social media expert's apartment in San Francisco turned up ball bearings, screws and components needed to make a homemade bomb designed to kill or maim, the FBI said in an affidavit unsealed Tuesday.
Investigators said they found the materials inside a bag at the apartment of Ryan Kelly Chamberlain during a search over the weekend. The discovery prompted a manhunt for the 42-year-old Chamberlain that ended with his arrest Monday in San Francisco.
The bag also contained a circuit board, screw top glass jar with batteries, a wire and a powdery green substance believed to be explosive material, FBI Special Agent Michael Eldridge said in the document.
"FBI bomb technicians believe that the circuit board described above was designed to serve as a remote control, allowing detonation of the device from afar," Eldridge said. "They further believe that the device was designed to maim or kill a human being or human beings."
The FBI has not said what, if any, specific plans Chamberlain might have had for the device, or how they were alerted to the material.
Though Chamberlain was considered armed and dangerous, FBI spokesman Peter Lee reiterated Tuesday that he did not seem to pose an immediate threat to public safety.
Chamberlain appeared in federal court Tuesday after being charged with one count of possession of an illegal destructive device. He was accompanied by a public defender and did not enter a plea. He had on the same shorts and sweatshirt when police arrested him near the Golden Gate Bridge.
On Saturday, as authorities arrived to search the apartment, they spotted Chamberlain and a woman leave and drive away.
Chamberlain returned on foot about 30 minutes later, when Eldridge said he identified himself and asked if they could talk in a nearby coffee shop. After a short discussion, Chamberlain asked if he could leave, and Eldridge said he could, the document states.
Authorities tried to follow him as he drove off but decided to pull back when he began speeding and running lights, Eldridge said. Authorities then searched the apartment and found the bomb materials.
"There were particular items that were found when we executed the search warrant that caused us great concern, concern for the public's safety in the event he decided to use those in such a fashion," FBI Special Agent in Charge David Johnson said. "It was going to be a significant problem."
Chamberlain was arrested by police officers who responded to a report that a person matching Chamberlain's description had been spotted, Police Chief Greg Suhr said.
Chamberlain had spotted the officers and was taken into custody after a brief chase and struggle, Suhr said. He described Chamberlain as someone who was in crisis and getting "more desperate by the moment."
Morgan Manos, who saw the arrest, captured it on video and sold it to TV stations, told reporters at the scene that Chamberlain looked surprised and frantic.
"They took him down hard," Manos said.
Alex Clemens, a partner of the San Francisco-based Barbary Coast Consulting, said Chamberlain is well known in city political circles and had been a fixture on the campaign trails for more than a decade. His work ended in the field several years ago.
Clemens, who briefly hired Chamberlain in 2009 for a project, said people who know Chamberlain are stunned.
"I believe there's been a failure in his support system. I'm sad for that," Clemens said. "I hope he will reach out to those who will help him."
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