A San Francisco man described as a social media expert and political consultant appeared in federal court on Tuesday charged with one count of possession of an illegal destructive device after an FBI search of his apartment reportedly turned up bomb-making components.

Ryan Kelly Chamberlain, 42, was arrested Monday after a three-day manhunt.

"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, quoted by The Associated Press. "They further believe that the device was designed to maim or kill a human being or human beings."

The San Francisco Chronicle says a bag inside his apartment contained the remote detonating circuit as well as ball bearings, screws and a model rocket engine.

"The items found Saturday in a bag allegedly belonging to Chamberlain make up the 'four components necessary to comprise an IED,' or improvised explosive device, according to the federal indictment," The Los Angeles Times reports.

The Chronicle reports that on Monday, with the man hunt well underway, "Chamberlain's 718 Facebook friends were jolted by a posting of an apparent suicide note titled 'Goodbye' — a letter he had apparently written Saturday, shortly after federal agents searched his Polk Street home and allegedly found explosives."

According to The Chronicle:

"Chamberlain said he had used a program, HootSuite, to delay the posting of the note, in which he bade farewell to loved ones and spoke about suffering from depression 'for as long as I can recall.'

" 'So much was broken from this past year-and-a-half, and from moments way back before that,' the three-page letter stated. 'I guess it was just insurmountable, and the time's up.'

"At one point Monday, a second note — also posted using HootSuite — showed up on Facebook and Twitter. It wasn't clear when the note was written, but Chamberlain indicated he had been following media reports about the raid and was compelled to correct them.

" 'A panicked update to my letter that should have posted by now,' he wrote. 'Nothing they're reporting is true.' "

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