A retired army colonel arrested over crimes during the Uruguayan dictatorship admitted to murder, kidnapping and torture, according to official documents released on Tuesday.
"I executed many people, kidnapped and imprisoned in various countries, for which I received congratulations from the army high command during the process and in democracy until last year," wrote Gilberto Vazquez in 2006.
The letter was revealed by the Mothers and Relatives of Disappeared Detainees in Uruguay after accessing the minutes of a 2006 army trial.
Ignacio Errandonea, a member of the relatives organization, said the court handed the letter to Carlos Diaz, the army commander-in-chief at that time, to decide whether or not the admission amounted to a crime.
Diaz ordered the trial to continue and said the alleged crimes would be "communicated in due course" to the defence minister.
The court "found Vazquez guilty of offending (military) honor by using a toupee" to escape detention "but not for all the barbarities he confessed to," said Errandonea.
"Where is the honor of those generals?"
"They hid these facts from the ministry, they hid these facts from justice," added Errandonea.
On Friday, the organization shared other minutes from the court case, in which Vazquez admitted to crimes against humanity during the dictatorship that lasted from 1973 until 1985.
"I had to kill, I killed and I have no regrets. I had to torture and I tortured," said Vazquez, who was eventually sentenced to 25 years in prison for the murder of 28 Uruguayans captured in Argentina in 1976.
He was taken before the military court after escaping from a military hospital by faking an illness to leave the prison where he was being held ahead of a possible extradition to Argentina to face charges of crimes committed during the dictatorship.
The mothers and relatives organization gained access to the court minutes following a request to the defense ministry for access to public information.