Operation Condor was a cooperative effort, ostensibly anti-Communist but working against multiple forms of dissent, among the 1970s-era military dictatorships of Argentina, Brazil, Bolivia, Chile, Paraguay and Uruguay. Manuel Contreras, head of the Chilean political police, is often considered the creator of the program,  started in 1975 on the birthday of Chilean military leader Augusto Pinochet. The secrecy of the program was breached almost accidentally, when a Paraguayan judge, looking for information about a specific political prisoner, found a number of archives about the entire program. 
It was an indigenous Latin American program, although the U.S. appeared to have some access to it. Thousands of persons were "disappeared" by Condor participation, often across national boundaries; the Spanish term for the "Disappeared ones" is Los Desaparecidos.
Torture was certainly present, and interesting observations can be made about the diffusion of torture among involved nations, showing patterns of cooperation.
While Chile may have initiated the program, some of the most intense activity was Argentinean.
U.S. Ambassador Raul Castro, in September 1978, after Vice-President Walter Mondale met with the head of the head of the Argentian junta (1976-1981), Jorge Rafael Videla, who led the country's military junta from 1976 to 1981, reported that Argentine Army Chief of Staff Roberto Eduardo Viola was positive about American Foreign Military Sales to Argentina. 
"A 1979 telegram reveals how U.S. policy placed U.S. officials in a moral and political predicament while dealing with those responsible for human rights atrocities. At a meeting with General Viola, then-U.S. Ambassador Raul Castro asked him to help clarify the fate of two recent disappeared Montonero insurgents, Mendizabal and Croatto. Viola responded without hesitation, "Mendizabal and Croatto were terrorists ... who were eliminated ... with my authorization."
A 1995 study put Brazil midway between Argentinean democratization, and the question if there had been serious change in Paraguay. 
Manuel Contreras, who was head of the Chilean intelligence agency, reported directly to Pinochet. Much took place inside the country, but the assassination of former Chilean Foreign Minister Orlando Letelier, in Washington in September 1976. Contreras, was imprisoned, in 1993, for his role in the killing. 
Alfredo Stroessner, Paraguay's former military dictator, was charged in connection with disappearances related to Operation Condor, but us in Brazil, from which he is apparently safe from extradition. General Alejandro Fretes Davalos, head of the Paraguyan military was charged in September 2005 with similar matters, but denied knowledge and responsibility, saying it was the responsibility of intelligence and police officials, who were dead. 
In 1992, documents on Paraguayan participation in Condor were discovered.
- Robert Plummer (8 June 2005), "Condor legacy haunts South America", BBC News
- , IX. Operation Condor, Argentina: Reluctant Partner. The Argentine Government's Failure to Back Trials of Human Rights Violators, December 2001
- National Intelligence Council (September 18, 2000), CIA Activities in Chile
- The Pentagon and the CIA Sent Mixed Message to the Argentine Military: The Argentine Generals were "told by U.S. government officials" that Washington was "not serious and committed" to human rights, vol. National Security Archive Electronic Briefing Book No. 85, March 28, 2003
- Scott D. Tollefson, Civil-Military Relations in Brazil: The Myth of Tutelary Democracy
- Osorio, Carlo and Mariana Enamoneta, ed. (21 December 2007), Rendition in the Southern Cone: Operation Condor documents revealed from Paraguayan "Archive of Terror", vol. National Security Archive Electronic Briefing Book No. 239— Part II