The Trelew Massacre was the retaliatory government killing of 16 militants of different Peronist and left organizations held as political prisoners in Rawson Penitentiary. The prisoners were recaptured after an escape attempt and subsequently shot down by marines led by Lieutenant Commander Luis Emilio Sosa in a simulated new attempt to escape. The marines forced the prisoners to fake a new escape, then executed them as revenge by the dictatorship for the successful escape of some of their comrades during the initial prison break. The massacre took place on the morning of 22 August 1972 in the Almirante Marcos A. Zar Airport, an airbase of the Argentine Navy near the city of Trelew, Chubut in Patagonia.