CHINO, Calif. — Blood-soaked mattresses, singed bedding and abandoned medical supplies littered the campus of a Southern California prison Tuesday, a testament to the mayhem and violence of a weekend riot that shut down part of the institution and injured about 175 inmates, some critically. Prison officials staged a tour of the devastation at the California Institution for Men in Chino to reveal the extent of the racially motivated riot that broke out Saturday evening and raged for four hours before guards could bring it under control. Seven of the eight units in the prison's Reception Center West, one of...