"This is the Argentine army. We've come for Monica Mignone," they yelled. Mr Mignone, a former university rector, was forced to let them in and watch as they roused his 24-year-old daughter, a beautiful, raven-haired educational psychologist, from her bed and led her away. Like many other parents whose children were detained that day and over the next seven years, he never saw her again. An official inquiry reported 9,000 missing. Relatives speak of 30,000.
Nineteen years later, as a wall of military silence finally begins to crumble, Mr Mignone, now a leading human rights activist, believes he finally knows his daughter's fate. "She was almost certainly interrogated for a few days, drugged, carried on to a military plane and dumped alive over the Rio de la Plata or the Atlantic," he said. Her crime? Apparently to have joined other young Catholics from a local church in helping to educate poor children in the Bajo Flores slums, a suspected breeding ground for leftist guerrillas.
Speaking in the third-floor apartment at 2949 Avenida de Santa Fe from which his daughter was abducted, Mr Mignone, now 72, said he based his long-suspected conclusions on horrific recent revelations by a retired navy captain, Adolfo Scilingo, that thousands of desaparecidos (disappeared ones) had been dumped from aeroplanes in flight, naked, drugged but alive, to let the ocean and sharks make identification impossible. No mass graves, no evidence - and what complicitous Catholic priests at the time thought a "less violent, more Christian method" to deal with "subversives."
Capt Scilingo served in the capital's Naval Mechanical School - known by its Spanish initials, the ESMA - and used as a detention centre for the desaparecidos. Body-dumping duty was carried out every Wednesday, rotated among junior naval officers so that the entire service would be equally implicated "in a kind of communion", and blessed by naval chaplains. Sworn to secrecy, the junior officers referred to the weekly duty simply as "el Vuelo" (the Flight).
El Vuelo, now the title of a book in which Capt Scilingo reveals his story to journalist Horacio Verbitsky, has reopened old wounds in Argentina, and became an emotive issue in campaigning for today's elections. President Carlos Menem, who in 1990 pardoned Argentina's military chiefs for their "dirty war" activities from 1976 to 1983, is under intense pressure to rescind that decision if, as expected, he is re-elected today for a new four-year term. The "Mothers of the Plaza de Mayo", mothers of desaparecidos who have, for almost 20 years, demonstrated in the Buenos Aires square, are demanding that Mr Menem identify all those who took part in atrocities and that all be punished.
The present military chiefs have all admitted this month, for the first time, that atrocities occurred, albeit without confirming Capt Scilingo's details. The army chief, General Martin Balza, said soldiers had "employed illegitimate methods, including the suppression of life". The air force chief, Brigadier Juan Paulik, spoke of "serious errors of procedure".
Following Capt Scilingo's lead, other junior officers and gendarmes have confirmed that detainees - workers, students, teachers, intellectuals, nuns and journalists suspected of having had contacts with "subversives" - were routinely tortured with electric cables clipped to their genitals. Dogs trained to bite off testicles were widely used, according to gendarme Federico Talavera. Those who died of torture before they could be taken on the Flight were incinerated to destroy all trace.
Capt Scilingo's revelations, including his description of how military chaplains comforted the torturers, and justified atrocities by saying, "The wheat has to be separated from the chaff", did not surprise Mr Mignone. Ten years ago, in his book Church and Dictatorship, he chronicled complicity by Catholic churchmen. The Church has promised a formal response to the latest allegations. Five bishops recently admitted that "for the rest of our lives we will carry on our consciences the regret at not having done much more".
As for Capt Scilingo, 45, he was jailed last week on suspicion of an investment fraud after his navy retirement. Friends say he was set up. His story, which few Argentinians doubt is accurate, last week tormented the nation in the newly published El Vuelo.
"Those who were to take the Flight were in the basement. They were told they were being moved to the south and therefore needed vaccinations. One of the doctors there gave them a dose that knocked them out. We loaded them on to navy lorries, took them to the Aeroparque and loaded them on to the plane like zombies. They were happy. They didn't know they were going to die. After take-off, the doctor on board gave them a second dose ... They were sound asleep. The doctor then went to the cockpit ... We stripped them, opened the back door and tossed them out, naked, one by one. There were 15 to 20, every Wednesday." Capt Scilingo himself had tossed out 30 people.
He turned to drink and drugs to deal with the memories. He once almost fell from a plane while tossing out a body, and still has nightmares in which he falls out and wakes up just before he hits the ground.