Question: What judicial trial of the members of the "de factor" military government that ruled Argentina during the dictatorship of the Proceso de Reorganización Nacional ("el proceso") was served by Chief Justice Leon Arslanian?

Context paragraphs:
Alfredo Astiz: Alfredo Ignacio Astiz (born 8 November 1951) is a former commander, intelligence officer, marine and naval commando who served in the Argentine Navy during the military dictatorship of Jorge Rafael Videla during the Proceso de Reorganización Nacional (1976–1983).  He was known as "El Ángel Rubio de la Muerte" (the "Blond Angel of Death"), and had a reputation as a notorious torturer.  He was discharged from the military in 1998 after defending his actions in a press interview.

Ricardo Cavallo: Ricardo Miguel Cavallo is a retired Argentine naval lieutenant commander.  Under the name Miguel Angel Cavallo and pseudonym "Serpico", he served as an officer of the National Reorganization Process ("El Proceso"), the military junta that ruled Argentina from 1976 to 1983.  As a member of the secret G-322 operations, he was charged with committing kidnapping, torture and murder of hundreds of political dissidents.

León Arslanián: León Arslanián (born November 30, 1941) is an Argentine lawyer, jurist and public official who notably served as Chief Justice in the tribunal that presided over the 1985 Trial of the Juntas.

Trial of the Juntas: The Trial of the Juntas (Spanish, Juicio a las Juntas) was the judicial trial of the members of the "de facto" military government that ruled Argentina during the dictatorship of the Proceso de Reorganización Nacional ("el proceso"), which lasted from 1976 to 1983.

National Reorganization Process: The National Reorganization Process (Spanish: "Proceso de Reorganización Nacional" , often simply "el Proceso", "the Process") was the name used by its leaders for the military dictatorship that ruled Argentina from 1976 to 1983.  In Argentina it is often known simply as "la última junta militar" (the last military junta) or "la última dictadura" (the last dictatorship), because there have been several.

Full stop law: The Full stop law, Ley de Punto Final, was passed by the National Congress of Argentina in 1986, three years after the end of the military dictatorship of the Proceso de Reorganización Nacional (1976 to 1983) and restoration of democracy.  Formally, this law is referred to by number (Law No. 23492), like all others in Argentine legislation, but "Ley de Punto Final" is the designation in common use, even in official speeches.

The Trial of Mary Dugan (1931 film): The Trial of Mary Dugan (Spanish:El proceso de Mary Dugan; French:Le procès de Mary Dugan) is a 1931 American drama film directed by Marcel De Sano and Gregorio Martínez Sierra and starring José Crespo, Adrienne D'Ambricourt and Juan de Landa.

Law of Due Obedience: The Law of Due Obedience (Spanish: "Ley de obediencia debida" ) was a law passed by the National Congress of Argentina after the end of the military dictatorship of the Proceso de Reorganización Nacional (which started with a coup d'état in 1976 and ended in 1983).  Formally, this law is referred to by number (Law No. 23521), like all others in Argentine legislation, but "Ley de Obediencia Debida" is the only designation in common use, even in official speeches.

Malevo Ferreyra: Mario Oscar Ferreyra, better known as Malevo (June 17, 1945 – November 21, 2008) was an Argentine police chief.  Being a police officer during the Proceso de Reorganización Nacional, he participated in the Dirty War, fighting against left-wing guerrilla groups in Tucuman province.  After the return of democracy, he would become the chief of Tucumán Provincial Police.  In this position, Ferreyra became involved in the dubious death of a number of supposed criminals.  He would later be prosecuted and discharged from the force.  He shot himself in 2008, when facing his imminent arrest, and his suicide was broadcast live on national TV.

Haroldo Conti: Haroldo Conti (May 25, 1925 – 1976?)  was an Argentine writer, screenwriter, teacher and Latin professor.  On May 5, 1976 he disappeared during the Proceso de Reorganización Nacional military dictatorship, on this day the "Día del Escritor Bonaerense" (Day of the Buenos Aires Province writer) is held to commemorate this date of his kidnap.

Supporting paragraphs: León Arslanián Trial of the Juntas
Answer: Trial of the Juntas