An Argentinian former military officer has died of natural causes in Berlin just weeks before he was charged over the murder of 23 members of leftwing groups during the country’s military dictatorship. The 75-year-old ex-navy officer was suspected in the abduction, disappearance, torture and murder of 23 young people in 1976 and 1977, Berlin prosecutors said. They would not name the suspect, but the European Center for Constitutional and Human Rights (ECCHR), which helped victims’ relatives file a case against the suspect, named him as Luis Kyburg. An estimated 30,000 people disappeared during Argentina’s military dictatorship, which launched a violent campaign against suspected leftwing political critics in the 1970s and 80s. Kyburg was the alleged commander of an elite navy unit believed to be responsible for the deaths of at least 150 people, and escaped to Berlin in 2013 after fellow members of the military taskforce he belonged to were convicted in Argentina. He had dual Argentinian-German citizenship, and lived in apparent peace for seven years until his presence in the capital was revealed by Bild newspaper. After a lengthy investigation, which involved working with Argentinian officials, interviewing numerous witnesses, and searching his Berlin apartment, an indictment was filed this month. But it was then discovered that the man had died of natural causes in October, according to a statement from the Berlin prosecutors’ office. “The death of the accused abruptly ends the decades-long efforts of the relatives and investigative authorities in Argentina and Germany,” said Margarete Koppers, the Berlin attorney general. “This is extremely difficult and painful for the victims’ families, and they have my deepest sympathy.” Wolfgang Kaleck, the ECCHR’s general secretary, said it was regrettable that victims and their families were not able to see justice served, particularly as “there is a comprehensive and solid indictment from Berlin’s public prosecutor and most of Kyburg’s accomplices have been convicted by courts in Argentina”. After being arrested, the victims were taken to a marine base and tortured with the suspect’s knowledge, prosecutors said. Some were taken to other locations and released, before being shot in staged confrontations. Most were killed on “death flights” – where they were thrown to their deaths from planes, prosecutors said.