Ertl was born in Munich. After World War II her father immigrated to Bolivia, where he continued to film for some time and became a farmer. Monika Ertl came to Bolivia in 1952 when her father brought the family over from Germany. Her father established a new life in the farm "La Dolorida" where he was breeding livestock. In Bolivia, she accompanied her father on several filming expeditions and learnt to use both a film camera and firearms. Later, she entered a marriage briefly, but felt unhappy playing the "trophy wife" of a Bolivian-German mining engineer. After her divorce in 1969, she became involved with the survivors of Che Guevara's routed guerrilla movement, the National Liberation Army of Bolivia. After helping out in minor occasions she finally joined the political underground. She began a relationship with the ELN leader, the successor of Che Guevara. Peredo was killed by the secret service of Bolivia on 9 September 1969. In Germany, she became known as "Che Guevara's avenger" because of her involvement in the 1971 murder of Colonel Roberto Quintanilla Pereira in Hamburg, Germany: although this has never been completely proven it can safely be assumed that she did shoot Quintanilla who, at the time, was serving in Hamburg as the Bolivian consul. A message found at the murder scene had written the wordsVictory or Death a slogan by the ELN. A former leader of the 'National Liberation Army' of Bolivia, Osvaldo "Chato" Peredo, confirmed, in an interview filmed by German director Christian Baudissin in 1988, that Quintanilla was a prime target of the ELN, because he had been responsible for ordering the hands of Guevara's corpse be cut off and sent to La Paz for further identification. He also states that Ertl "after carrying out the mission in Hamburg" returned to Cuba where she met with Régis Debray. After being under covert observation in Bolivia for several days she and another guerrilla were eventually ambushed and killed by Bolivian security forces on 12 May 1973 in El Alto, where she was reorganizing the ELN. According to Régis Debray she was also preparing the abduction of the former Gestapo Chief of Lyon Klaus Barbie to bring him to Chile and consequently to justice in France where he was wanted as a Nazi war criminal. At the time Barbie was known to be an adviser of the secret police in Bolivia. Her body was not turned over to her family to be buried and she rests in an unknown grave.
Popular culture
Ertl is among the prominent characters in a fictionalized account of her family, Los Afectos by Bolivian author Rodrigo Hasbún.
A documentary film was made called 'Wanted: Monika Ertl' about her life.
