MEXICO CITY — Protesters ransacked and burned government offices Monday in Chilpancingo, the capital of Guerrero state, in an explosion of outrage over the suspected kidnapping and murder of 43 students by corrupt local police. Anti-government rallies have been held in several Mexican cities since the students’ disappearance Sept. 26 and the subsequent discovery of mass graves outside Iguala, about 120 miles south of Mexico City. But on Monday, the protests turned violent.