By Laura Rena Murray
SAN FRANCISCO (Reuters) - Police have arrested a San Francisco public relations consultant who was the subject of a nationwide manhunt after federal authorities found explosive materials in a weekend raid on his apartment, authorities said.
The San Francisco Chronicle reported that Ryan Kelly Chamberlain, 42, sent an automated farewell message timed to go out on Monday to family and friends via social media in which he spoke of his depression, romantic heartbreak and loss of job.
"So much was broken from this past year-and-a-half, and from moments way back before that," the Chronicle cited the three-page letter as saying. "I guess it was just insurmountable, and the time's up."
Chamberlain was arrested by the FBI and local police, the FBI said in a Twitter message late on Monday.
Authorities said no known chemical, biological or radiation weapon threat was found in a search of his home on Saturday that turned up explosive materials.
Chamberlain was taken into custody in the area of San Francisco's Golden Gate Bridge after authorities gave chase throughout the day, though his method of travel was unclear, ABC News reported, citing an unnamed law enforcement source.
"We had been close to him all afternoon," ABC quoted the source as saying. "We never could quite get to where he was. We would find out he was in a particular location 10 or 15 minutes after he was there. He was working his way through the city."
Chamberlain was a public relations contractor for several local tech and marketing companies, his online resume shows.
He taught a "grassroots mobilization" course for one semester at the University of San Francisco in 2011, but has not been associated with the school since, according to Anne-Marie Devine, a spokeswoman for the California college.
(Additional reporting by Eric M. Johnson; Editing by Cynthia Johnston and Mark Heinrich)