(CNN) -- Federal authorities in Argentina are investigating the death of a key witness in a human rights trial that started Tuesday, the official news agency reported.
Jesus Gonzalez, known as "el Flaco" or "the skinny one," was found dead Friday in the central Argentinian city of Cordoba in what initially was characterized as a suicide, said the government-run Telam news agency.
Gonzalez was scheduled to testify in the trial of former army Gen. Luciano Benjamin Menendez and five others accused of human rights violations during Argentina's military dictatorship from 1976 to 1983. They are accused of illegal detention and committing torture and aggravated homicide.
Menendez previously had been accused of nearly 800 crimes but had been immune because of a special amnesty law against top officials in the dictatorship. After the immunity laws were lifted in 2006, he was found guilty of kidnapping, torture and murder and sentenced last year to life in prison. He was a top commander in Cordoba during the dictatorship.
Gonzalez was a guard at a secret detention center in Cordoba during that time.
Gonzalez was found in the bathroom of his home Friday night with a fatal stab wound to the chest, Telam said.
Local judge Maria Antonia de la Rua had routinely started to investigate the death before becoming aware of Gonzalez's connection to the trial, federal judge Gustavo Vidal Lascano told Telam. The investigation was transferred to federal police after the dead man's link to the trial was established.
Three charges have been consolidated in the trial, which centers on what is known an the "Albareda Case." Fermin Albareda was a member of the political wing of the People's Revolutionary Army, Argentina's communist party during the dictatorship. He was tortured and killed in 1979 at the secret prison where Gonzalez worked.
The prisoners at these clandestine detention centers included students, labor leaders, intellectuals and leftists who had run afoul of the dictatorship because of their political views. Most were dragged off the street or otherwise summarily arrested and held without trial.
As many as 30,000 people disappeared or were held in secret jails and torture centers during what is commonly called "the dirty war."
Argentinean and Spanish officials announced the arrests last month of two former military officers accused of piloting aircraft from which drugged and blindfolded prisoners were hurled to their deaths in the Atlantic Ocean or the Rio de la Plata.
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