Alfredo Astiz, a former Argentinian navy captain who led a death squad during military rule from 1976 to 1983, turned himself in to police yesterday after an Italian court sought his arrest for the alleged murder of three citizens.
The arrest marked the first time an Argentinian judge has followed up a petition from a foreign court involving a human rights case dating back to military rule.
Judge Maria Servini de Cubria accepted the case as it involved child theft, a crime not covered by previous Argentinian amnesty laws which granted immunity from prosecution for crimes committed during the dictatorship.
Ms Angela Aieta, Mr Giovani Pegoraro and his pregnant daughter, Ms Susana Pegoraro, were kidnapped by the army between 1976 and 1977.
Ms Pegoraro was five months pregnant and gave birth in the Navy School of Mechanics (ESMA), a death camp located in central Buenos Aires, where 5,000 political suspects were tortured, most of them to death.
Pregnant women were often killed after giving birth, their infants handed over to military families. Ms Pegoraro's daughter has been traced to Mar del Plata, a city south of Buenos Aires, according to Argentina's leading newspaper, Clarin.
Capt Astiz, known as "the angel of death", infiltrated exiled families in France, then passed himself off as the brother of a "disappeared" man to join the ranks of the Mothers of the Disappeared.
In December 1977 he led security forces to a church where the Mothers' organisation met, sealing the fate of two French nuns, who were kidnapped and killed.
Argentinians were shocked to learn that Capt Astiz was still on the navy intelligence payroll in 1998, despite a life sentence in absentia delivered against him by a French court for his role in the murder of the nuns.
In the same interview he boasted that he was "the best-trained man in Argentina to kill journalists and politicians", earning himself a three-month suspended jail sentence.
He narrowly escaped extradition to France in 1982 after he surrendered to British troops in the Falklands, while inside Argentina he has been declared persona non grata by several state councils, further limiting his freedom of movement.
Capt Astiz has been attacked several times by relatives of his victims who recognised him on the streets of the capital city.
"Astiz is an ugly symbol of Argentina's horrific past," said Ms Estela Carlotto, spokeswoman for the Grandmothers of the Disappeared. "I hope this case turns out different," she added, referring to previous failed attempts to secure the extradition of Argentinians wanted by foreign courts.