BUENOS AIRES, Nov 18 (AFP) - As Argentina gears for a trial from one of the most shameful periods of its history, Luis Bianco's painful search for justice brought him to the building where his mother was tortured and killed.

"They held them here before taking them out and throwing them into the sea," said Luis Bianco, a 53-year-old taxi union employee.

Here in the Naval Mechanics School, his mother, Maria Ponce de Bianco, was tortured along with scores of political dissidents during Argentina's 1976-1983 military dictatorship.

Alfredo Astiz, known as the "Blond Angel of Death," is due to face trial trial for his alleged involvement in the disappearance of Bianco, other dissidents, a Swedish adolescent and two French nuns during the dictatorship's "dirty war" against leftist insurgents.

Bianco and three others were kidnapped over several days in December 1977.

Astiz is accused of having infiltrated the "Mothers of the Plaza de Mayo," a group representing the mothers of disappeared individuals, by faking his identity as Gustavo Nino, brother of a vanished person.

But his trial was postponed for a second time Tuesday, with no date yet set for a hearing in a move frustrating those desperately in search of answers.

"I am proud to be the son of these mothers who created a unique movement. They were alone, in the middle of a crackdown, and they were called the Crazy Women of the Plaza de Mayo," said Bianco.

Tears streamed down his cheeks as he recalled his mother's body, found with her hands cut off at the General Lavalle Cemetery, 350 kilometers (220 miles) south of Buenos Aires, and identified in 2005.

"It was the only body without hands. I can't forget it. This image haunts me," said Bianco. Last time he visited the site in 2005 his emotions overwhelmed him and he collapsed.

His mother was among the first to join the movement of women who have protested the disappearances before the presidential palace every Thursday since 1977 demanding news about their sons and daughters.

Her daughter, Alicia, had been kidnapped in 1976, when she was just 21 years old.

"Thirty-two years of fighting: how many times did they circle the Plaza?" Bianco asked, with a brief smile.

In this sinister building, people were tortured in the basement and the attic while navy officers slept peacefully on the first and second floor.

Nearly 5,000 people were tortured there and later executed, often thrown alive from planes flying above the Rio de la Plata. Only a few hundred survived the ordeal.

The Argentine dictatorship is blamed for the disappearance of 30,000 individuals, according to rights groups.

Astiz has already been sentenced to life in prison in Italy, in 2007, and France, in 1990, for the murder of three Italians and the two French nuns -- Leonie Duquet and Alice Domon.

Bianco said he takes "pity on this coward who kidnapped women who only wore a white cloth on their heads," referring to the women's distinctive headscarves.

Renamed the Space for Memory and for the Promotion and Defense of Human Rights in 2004, ESMA was designated this year a UNESCO human rights center, as Argentina continues to debate the tortures 26 years after the return of democracy.

Since Nestor Kirchner came to power in 2003, Argentine authorities have sought to bring to justice those accused in the wave of disappearances. (By Oscar Laski/ AFP)