The exact chronology of the repression is still debated , however , as in some senses the long political war started in 1969 . Trade unionists were targeted for assassination by the Peronist and Marxist paramilitaries as early as 1969 , and individual cases of state-sponsored terrorism against Peronism and the left can be traced back to the Bombing of Plaza de Mayo in 1955 . The Trelew massacre of 1972 , the actions of the Argentine Anticommunist Alliance since 1973 , and Isabel Martínez de Perón 's " annihilation decrees " against left-wing guerrillas during '' Operativo Independencia '' ( translates to Operation of Independence ) in 1975 , have also been suggested as dates for the beginning of the Dirty War
Trelew massacre
Trelew massacre
Argentina