When violence erupted in downtown Seattle in late May, Ed Little was disturbed by the images of looting and violence he saw on television. “I thought it was crazy. That shouldn’t be happening at all,” said Little, who believed that peaceful protests against police brutality were hijacked by criminals. Weeks later, there was a knock at the door of Little’s Everett apartment when police came to arrest his 25-year-old son and search the family’s apartment. “It’s hard to believe. We don’t know Jake like that. It’s not the kind of boy he is,” Little said. In September, federal prosecutors accused...