Former Mexican president Luis Echeverria Alvarez, known for brutal repression of political opponents, has died at the age of 100, the government said Saturday. Echeverria, who belonged to the once dominant Institutional Revolutionary Party, or PRI, died Friday in the city of Cuernavaca, President Andres Manuel Lopez Obrador wrote in a message of condolence. A lawyer by trade, Echeverria was accused of ordering massacres of students in 1968 when he was interior minister and again in 1971 when he was president, both times in Mexico City. He stood trial over the death of some 200 student proteste…