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.