After the coup d'état by the armed forces against Allende's government on Tuesday 11 September 1973, Miguel was one of the main guerrilla leaders that remained after many fled the country. This proved to be a precarious existence and Miguel was killed in a gun fight with agents of the Dirección de Inteligencia Nacional (DINA) (National Intelligence Directorate) in the slum home where he was carrying out his clandestine operations. He is buried in the Cementerio General de Chile in Santiago and the medicine faculty of the Superior Institute of Medicine of La Habana, Cuba, has been named in his honor.