( CNN ) -- Ryan Kelly Chamberlain II , a San Francisco man accused of having explosive materials at his home , is in custody , an FBI source said Monday . Chamberlain was arrested in Crissy Field , a scenic waterfront area where the Golden Gate Bridge spans the Pacific entrance to San Francisco Bay , a U.S. law enforcement official said . Police have cordoned off the area to search Chamberlain 's white Nissan Altima , the official said . Authorities had been looking for him since the weekend . Chamberlain , 42 , was last seen Saturday south of San Francisco , the FBI said . `` We do n't know the intent or motive yet , '' FBI agent Peter Lee told reporters over the weekend , stressing there was no threat to public safety . The FBI said then that Chamberlain should be considered armed and dangerous . Chamberlain 's block was closed for some 15 hours over the weekend as investigators searched and cleared the area , CNN affiliate KTVU reported .
NEW : This means the product will ship as received by the manufacturer, sealed, with all advertised components, and with the manufacturer warranty. Ryan Kelly Chamberlain II , 42 , is accused of having explosive materials at his home . He was last seen Saturday south of San Francisco , according to the FBI .