The Dirty War , also known as the Process of National Reorganization , was the name used by the Argentine Military Government for a period of state terrorism in Argentina from roughly 1974 to 1983 (some sources date the beginning to 1969), during which military and security forces and right-wing death squads in the form of the Argentine Anticommunist Alliance (Triple A) hunted down and killed left-wing guerrillas, political dissidents, and anyone believed to be associated with socialism. The victims of the violence were 7,158 left-wing activists, terrorists and militants, including trade unionists, students, journalists and Marxists and Peronist guerrillas and their support network in the Montoneros believed to be 150,000-250,000-strong and 60,000-strong in the ERP, as well as alleged sympathizers. The official number of disappeared is reported to be 13,000. Some 10,000 of the "disappeared" were guerrillas of the Montoneros (MPM) and the Marxist People's Revolutionary Army (ERP). The leftist guerrillas caused at least 6,000 casualties among the military, police forces and civilian population, according to a National Geographic Magazine article in the mid-1980s. The "disappeared" included those thought to be a political or ideological threat to the military junta, even vaguely, and they were killed in an attempt by the junta to silence the opposition and break the determination of the guerrillas. The worst repression occurred after the guerillas were largely defeated in 1977, when the church, labor unions, artists, intellectuals and university students and professors were targeted. The junta justified this mass terror by exaggerating the guerrilla threat, and even staged attacks to be blamed on guerillas and used frozen dead bodies of guerilla fighters that had been kept in storage for this purpose.