An appeals court in Rome sentenced 24 people to life in prison on Monday, including senior officials in Chile, Paraguay, Uruguay, Brazil, Bolivia and Argentina’s military dictatorships.

The officials were found to have been involved in the US-backed Operation Condor, which took place in the 1970s and 80s. Operation Condor involved tracking down and removing political opposition to South American military rule, and the exact number of people who were killed through this operation is not known. The case before the court focused on the disappearance of 43 people, 23 of whom were Italian citizens. There is evidence provided by prosecutors in South America and Italy that at least 100 left-wing activists were killed in Argentina.

The prosecutors applied the universal jurisdiction precedent from the 1998 arrest in London of Chilean dictator Augusto Pinochet. They also referenced the 2016 conviction of members of Argentina’s military dictatorship, which confirmed the existence of Operation Condor for the first time.

The trial began in 2015, and is a result of years of pressure from the families of the victims who were kidnapped and assassinated. Only one of the 24 people convicted and sentenced to life in prison is in Italy. The other 23 were sentenced in absentia, and many are already serving jail time in their home countries. The European Convention on Human Rights protects the right to a fair trial, under Article 6. The European Court of Human Rights has found that a trial in absentia does not infringe this right, provided that specific conditions are met. Those accused must have “effective knowledge of the proceeding,” they must be “legally represented and have effective assistance of counsel,” and they should have “the right to retrial.”

Among those sentenced were former Bolivian Interior Ministor Luis Arce Gomez, Peruvian ex-President Francisco Morales Bermudez, former Uruguayan Foreign Minister Juan Carlos Blanco, and a former deputy intelligence chief from Chile.

Before the sentences can be carried out, the ruling must be confirmed by the Supreme Court of Cassation, which considers whether the judgements made by other courts were reached in accordance with the law.