An Argentine ex-police officer linked to the murder of hundreds of people during the 1976-1983 military dictatorship was on a plane to Buenos Aires on Monday, after France extradited him to face trial over the disappearance of a student.
Mario Sandoval was arrested Wednesday at his home near Paris, after French authorities gave the final go-ahead for his extradition, ending an eight-year legal battle.
The 66-year-old who had been living in France since 1985 and obtained French citizenship with few aware of his full identity, was sent back on a plane that left Paris around midnight on Sunday.
"Everything happened as expected," a lawyer for the Argentine state told AFP.
Argentina suspects that Sandoval took part in more than 500 cases of kidnappings, torture and murder at a time when some 30,000 were "disappeared" during the dictatorship.
But the extradition concerns only the alleged kidnapping in October 1976 of Hernán Abriata, an architecture student whose body has never been found.
Argentine authorities say investigators have several witness accounts linking Sandoval – known there as the "butcher" of the dictatorship -–to Abriata's killing.
Sandoval's lawyers had argued that he would not get a fair trial in Argentina where he would face torture or poor detention conditions.
But their appeals to the European Court of Human Rights to take up his case failed.
Abriata was detained at the notorious ESMA navy training school in Buenos Aires, where an estimated 5,000 people were held and tortured after the military coup of 1976 -- many of them thrown from planes into the sea or the River Plate.
Sophie Thonon, a lawyer acting for Argentina, told AFP that Abriata's 92-year-old mother Beatriz Cantarini de Abriata had been "desperately waiting" for Sandoval to "explain himself before Argentine justice".
Sandoval, who has dismissed the accusations as fabrications, fled Argentina after the military junta fell.
Despite taking French nationality he can be extradited as the alleged crime took place beforehand.
Sandoval was a professor at the Sorbonne's Institute of Latin American Studies in Paris and the University of Marne-la-Vallée outside the French capital.
His colleagues at both schools called for his arrest when they recognised his picture during his legal battles.
The French Council of State, which advises the government on legal matters, approved his extradition in August 2018, prompting Sandoval to appeal.
The Constitutional Council determined that no statute of limitations could be applied to an "ongoing" case, citing the fact that Abriata's body has never been found.
"I hope consular officials... will ensure that the conditions of his detention pending trial will be decent and limited in time," Sandoval's lawyer Jerome Rousseau told AFP.