Lawyers defending Adolfo Scilingo, an Argentine former navy officer on trial in Spain for genocide, have said he should be acquitted.
Scilingo's trial is the first for crimes against humanity in another country
Adolfo Scilingo faces 30 counts of genocide, 30 of murder, 93 of physical injury and 255 of terrorism.
The crimes were allegedly committed in the "Dirty War" of the 1970s/80s when Argentina was under military rule.
But his defence says that there is not enough evidence to link him to the alleged crimes.
"We ask the tribunal to acquit Adolfo Scilingo," his lawyer Fernando Martinez Morata said to the three-judge panel at Madrid's National Court.
"I have reached the conclusion that [the aim of the trial] is to judge a regime, a system, an activity which is surely reprehensible... through Adolfo Scilingo," he added.
Spanish prosecutors have requested a prison sentence of 9,138 years for Mr Scilingo, whose trial started in mid-January.
It is Spain's first trial involving human rights crimes committed abroad.
A verdict is due to be announced on 19 April.
Mr Scilingo, 58, now denies the charges against him.
But in 1997 he went to Spain voluntarily and testified before Judge Baltasar Garzon, who was investigating crimes committed during Argentina's and Chile's military dictatorships.
In a taped confession, Mr Scilingo spoke of the so-called "death flights", in which dissidents were stripped naked and thrown alive into the ocean from military planes.
He admitted taking part in two flights and spoke of other tortures committed at the Buenos Aires Navy School of Mechanics, which was used as a torture centre at that time.
Mr Scilingo later retracted his confession, saying his testimony was fabricated in order to prompt an investigation into the atrocities committed under the regime.
According to human rights groups, up to 30,000 political opponents were kidnapped, detained and later executed between 1976 and 1983.
Under Spanish law, prison terms cannot normally exceed 40 years, but for convicted members of Basque separatist group Eta it is not uncommon to be handed down sentences of hundreds or even thousands of years.