noun, masculine/feminineplural: exrehenes
former hostage
“En lo mejor de su ataque “al imperialismo” se presentó el Comandante del Regimiento acompañado de uno de los exrehenes, los que sin decir pío lo ensangrentaron a golpes.” — In the best of [someone’s] attack ‘on imperialism’ he was presented to the regiment commander accompanied by one of the former hostages, whom they wordlessly hit until he bled.
From ex- + rehén.