Complex sentence: The guilty party turned out to be the Carabineros'secret service, and the Caso Degollados (The Beheaded's Case) caused General Mendoza's resignation on August 2,1985 and was replaced by General Rodolfo Stange.
Split into simpler sentences: The guilty party turned out to be the Carabineros'secret service, and the Caso Degollados (The Beheaded's Case) caused General Mendoza's resignation. He officially resigned on August 2,1985 and was replaced by General Rodolfo Stange.