The bodies of Ferreira; her husband, Claudionor Costa da Silva, 42; and a friend of the family, Hilton Lopes, 38, were found gagged, bound, and riddled with stab wounds in the Salvador Allende settlement, the Movement of the Affected by Dams (MAB) reported.
Although police are unsure of the motive behind the gruesome murder, landowner Fernando Ferreira Rosa Filho (also known as Fernando Shalom) was taken into custody and is believed to be the mastermind.
Solidarity with the BriBri indigenous peoples in Costa Rica & our comrades at @MAB_Brasil, who have lost activists to brutal murders in recent weeks for opposing plantations and dams on indigenous land.
Ferriera was a strong force empowering, working as the coordinator of the MAB for over 30 years. The social leader had been active in the community, pushing for human and environmental rights "since (the construction of) a dam destroyed the city where she lived," during the Brazilian military dictatorship in 1974, the organization said in a statement last week.
In a statement, Former President Dilma Rousseff mourned Ferreira’s passing, saying her death was "another sad moment in the history of the MAB, which just today celebrated the 'International Day of Water.' As its militants say, "water is for life, not for death!'"
Ferreira was the first social activist killed in Brazil's Amazon this year.