I recently watched a movie about Argentina's Dirty War "The Disappeared" about Argentina's Dirty War Los Desaparecidos and the babies of Los Desaparecidos who were adopted by families affiliated with the military government. This movie is available through Netflix DVD and I watched it in Spanish with English subtitles. It is directed by Peter Sanders. It is estimated up to 30,000 people disappeared and as many as 400 babies were taken and adopted by others. Of these babies, 77 have been discovered.
The dirty war actually started before the military government took over in March of 1976 as the result of a military coup. Isabel Peron was president before this. There had been a period of significant terrorist activity in the country. Some consider the dirty to have started as early as 1956. In 1956, Peronists attempted a coup against the government, under President Aramburu. The coup failed, but as a result General Juan Jose Valle was executed. Many consider him the first "Disappeared." Vigilantes and Terrorists, in the name of communist insurrection and also in the name of radical Peronists called Montoneros, created an atmosphere were terrorist attacks were quite common. In 1970 the Montoneros kidnapped the ex president Aramburu, and then murdered him. The government carried out a war with Peronist extremists called the Montoneros and the communist terrorists. When the military government took over, they became for focused on putting down the insurrection. However the sweep of the government, in order to get as many insurrectionists as they could, swept into organizations and families from which perhaps extremists had come, but themselves were not involved. They suspended civil rights, and many were tortured and murdered. Some were drugged, and then thrown from planes into the river, Rio de la Plata, to drown. Many were imprisoned at a naval hospital at Campo de Mayo where they were tortured. Civil rights groups put the number of disappeared as high as 30,000. Others have the number as low as 10,000. There were 11,000 cases for which the government later paid retribution. The communist organizations indicate 5000 of their number were killed, and 5000 Montoneros were also killed. That leaves up to 20,000 killed who were not directly affiliated with these organizations. It also depends on when you start counting the disappeared. Others fled the country in fear, leaving behind their property and homes. Others were tortured but then returned home (I think these were few.)
The military government ruled from 1976 to 1983. After losing the Falkland Islands (Islas Malvinas) War the government was vulnerable. Finally there were elections in 1983 with President Alfonsin elected. He issued a pardon against those involved in the dirty war, but since other presidents have reversed this policy. However very few of those involved, torturers and murders, have ever been tried or jailed.