MEXICO CITY (AP) — Mexican authorities announced Saturday that they are investigating the homicide of a mayor in San Miguel Amatitlan, Oaxaca, in the country’s latest case of political violence. Joel Bravo Martínez was gunned down Saturday, weeks after he reported that he feared for his life and requested protection from the state government, according to a statement from his party PAN. The Oaxaca state prosecutor’s office said in a statement that once it learned of the killing, the institution