SAN FRANCISCO — Federal investigators said 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, according to 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, plans Chamberlain might have had for the device, or how they were alerted to the material.
The Des Moines Register reports Chamberlain attended Johnston High School in suburban Des Moines, where school district spokeswoman Laura Dillavou said he was a student body president and athlete. He graduated in 1989.
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.