He emphasized the need for a "tribunal like Nuremberg, an international tribunal to try all those who participated in Operation Condor."

Ivan Donato, son of Chilean communist leader Jaime Donato, asked for an international court similar to the Nuremberg tribunal set up after World War II to judge the dictatorship's crimes against humanity.

He emphasized the need for a "tribunal like Nuremberg, an international tribunal to try all those who participated in Operation Condor."

His father disappeared in 1976 under the dictatorship of Augusto Pinochet and was taken to Villa Grimaldi, a former interrogation center of the Chilean secret police.

"My father was tortured in Villa Grimaldi, and they took him from there, put him in sacks with iron rails, and threw him in the sea," Donato said.

His father was a member of the Central Committee of the Communist Party of Chile, had Italian heritage which meant that a court in Italy could consider the case.

On July 8, life sentences were imposed on 24 former officials involved in Operation Condor, a campaign of political repression carried out in the 1970s and 1980s by South American dictatorships to eliminate political opposition.

An estimated 50,000 people were killed, 30,000 disappeared and 40,000 were arrested during the campaign in different Latin American countries, according to the Archives of Terror, documents related to a CIA-backed plan discovered in Paraguay in 1992.

It is for this reason, Ivan Donato has spent more than 40 years fighting to find the remains of his father, a struggle during which his mother went on a series of hunger strikes and the family was often harassed by Chilean security forces, including a police raid on their house in 1986 during which his brother Nelson was tortured.

It was then that the Donato family, apart from one of Ivan's four brothers, sought asylum as political refugees in Australia, where they have lived since.

They continued to pursue cases related to political repression during Pinochet's dictatorship.

Ivan expressed regreted that the Italian verdict only provided a semblance of justice to a handful of the victims, only those who had Italian citizenship or links to the country.

He added that "what's important is that it establishes that a genocidal crime took place. "During the Italian trial, former Chilean soldier Pedro Octavio Espinoza Bravo was convicted for the disappearance of Jaime Donato.

Ivan said that others, including Manuel Conteras, the former head of the DINA, the secret police under Pinochet's regime, and others involved in the operation have not been held to account.

Ivan was 16 when he last saw his father in 1976 when he visited him with his mother Mariana Nunez in one of the safe houses of the Communist Party.

He said his father had to hide after soldiers raided his house for the first time in 1974 and arrested and tortured him before his release.

"We began to talk about my brothers," he added. "He told me there that the situation was too difficult to return home and asked me to understand that. It had been very nice seeing him again after a meeting one week earlier because there had been times when we could not meet for one, two or three months."

Although he and his family were offered asylum in what was then Czechoslovakia, Donato continued to stay and participate in communist activities.

It is believed that he was arrested again in Conferencia Street in Santiago along with many of his associates when they were attending a clandestine party meeting.

Officers working under Contreras, one of the architects of Operation Condor, "tortured him, hit him, beat him and after that kept him there for a couple of hours to wait for the others to arrive," Ivan said in a faltering voice at his house in western Melbourne.

"After that they took him to Villa Grimaldi and nobody used to come out alive from that place at the time."

The DINA detention center was where around 4,500 people were kept during the Pinochet regime and at least 240 were disappeared or killed.

Nobody knows how long Jaime was kept in Villa Grimaldi, but it is known through testimonies of DINA officers that he was "put in a sack and thrown in the sea" off the coast of San Antonio, a city around 100 km (62) west of Santiago.

Soon after the Conferencia street arrests, the DINA arrested the deputy general secretary of the Communist Party Victor Diaz, one of seven disappearances which led to Chile seeking the extradition of former DINA agent Adriana Rivas from Australia in 2014.

Rivas, who is believed to be have been a part of the Lautaro Brigade, an elite death squad of the DINA, and the former secretary of Contreras, has denied all charges.

Testimonies from detainees say that she was a ruthless participant in the interrogations carried out at the brigade headquarters in the barracks of Simon Bolivar Avenue in Santiago.

Although the cases of Diaz and Jaime are not directly linked, Ivan believes that Rivas could possess knowledge about what happened to his father.

"They could not have functioned without having complete information about what was happening at the moment, and a week before she reached Victor Diaz, Conferencia Street was raided," he said.

Ivan added that even if Rivas did not have direct knowledge, she would have archived it for Contreras.