[4][a] The region was chosen because it consisted of a hotspot of tension between peasants and developers (miners and public works contractors) attracted by the investment opportunities offered by the recent discovery of the nearby Carajás iron ore mine.

Of these, fewer than twenty survived - among them José Genoino, later president of the Workers' Party, who was arrested by the Army in 1972 during the first stage of military operations.

The vast majority of combatants, primarily composed of former college students and self-employed workers, were killed in battle in the jungle or executed after arrest and torture during the final stages of military operations in 1973 and 1974.

[2][7] The military intervention by the then military dictatorship to eliminate the guerrillas focus in the region, "the Araguaia guerrilla" can be divided into 4 phases:[8] When democracy was being restored, in 1982, family members of 22 of the disappeared persons brought proceedings in the Federal Court of Rio de Janeiro, asking for the whereabouts of the disappeared persons to be established and their remains located so that they could be given a decent burial and their death certificates could be registered.

[16] On April 29, the Supreme Federal Court decided, by a vote of 7 to 2, to uphold the 1979 Amnesty law, which prevents the trial of those accused of extrajudicial killings and torture during the military regime.