French police said Wednesday they had arrested Mario Sandoval, a former police officer wanted in his homeland Argentina for alleged involvement in the torture and disappearance of a student.
French officers tracing suspects wanted for crimes against humanity arrested Sandoval, accused over the offence which happened during Argentina's 1970s military dictatorship, in an eastern Parisian suburb.
He now faces extradition after French authorities in May rejected an appeal made against his return on the grounds the statute of limitations had expired.
"The extradition of Mario Sandoval to Argentina is henceforth definitive and will go ahead in a maximum of seven days," a statement from the French Gendarmerie read.
Sandoval, 66, is wanted over the alleged kidnapping in October 1976 of Hernán Abriata, an architecture student whose body has never been found, as well as a slew of other disappearances.
Argentine authorities say investigators have several witness accounts specifically alleging a link between Sandoval and the killing of Abriata.
He fled Argentina after the military junta fell and obtained French nationality in 1997, prompting his home country to seek an international arrest warrant in 2012 on charges of torture, kidnappings and murder.
Sandoval says the accusations are fabrications.
The French Council of State, which advises the government on legal matters, approved his extradition in August 2018 after years of legal wrangling, prompting Sandoval to appeal.
However, 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.
Abriata was detained at the notorious ESMA navy training school in Buenas 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 Plata river.
Despite Sandoval taking French nationality under French law he can be extradited as the alleged crime took place beforehand.
The junta finally ceded power in 1983 after a reign which human rights groups say saw 30,000 people disappear, presumed killed.
Argentina suspects that Sandoval took part in over 500 cases of kidnappings, torture and murder because around a dozen people have given testimony against the former police officer.
Sandoval's defence counsel said his client feared he would not receive a fair trial in Argentina and would take the case to the European Court of Human Rights over a "violation by France of its European commitments."
Laura Abriata, Abriata's 43-year-old sister, said the French decision was "the news we have anxiously been waiting for. Now it is confirmed after so many years," she said, noting Argentina had asked France to act almost eight years ago, setting in train "an arduous process of highs and lows."
She added that "now it will not be long before he arrives in Argentina to be tried under all constitutional guarantees which not all the Argentinian disappeared enjoyed."
Sophie Thonon, a lawyer acting for Argentina, told AFP that Abriata's 92-year-old mother had been "desperately waiting" for Sandoval to explain himself before Argentine justice."