The memo explained that terrorists were captured at gunpoint, hooded, and transported to an interrogation center where they were stripped of their clothing and placed inside a cell.

Their senses were then battered by severe temperature fluctuations and noise from loudspeakers — “screaming, sirens, and whistles” — before they were interrogated by “one or more agents,” who demanded they confess to the crimes of which they were accused.

If detainees refused to confess, or if the agents believed the detainees were withholding valuable intelligence information, they were subjected to a combination of physical and mental torture techniques until a confession was extracted.

That could describe the methods CIA officers and contractors used after 9/11 when detainees were rendered, flown to black site prisons in Eastern Europe, and subjected to a brutal combination of so-called “enhanced interrogation techniques” like waterboarding, painful stress positions, and cramped confinement. But these disclosures actually come from a recently declassified 1973 State Department cable pertaining to Brazil’s systematic torture of leftist dissidents between 1964 and 1985.

'The shock felt by the individual, though reportedly light in intensity, is constant and eventually becomes almost impossible to withstand.'

That cable, titled “Widespread Arrests and Psychophysical Interrogation of Suspected Subversives,” along with dozens of other declassified US government documents like it, was hand-delivered by US Vice President Joe Biden on June 17 to Brazilian President Dilma Rousseff after he arrived in the country to watch the US compete in the World Cup.

The diplomatic gesture from the Obama administration was meant to help Brazil’s National Truth Commission uncover and reconcile its past human rights abuses, and was made after news reports revealed that the National Security Agency had tapped Rousseff's cell phone and spied on other Brazilian government agencies, leading to a breakdown in relations between the two countries.

Rousseff, a former political prisoner who was tortured by the country’s former military dictatorship, established the Truth Commission two years ago. The commission, which is now in its final phase, posted the documents on its website.

The United States covertly supported the military coup that deposed President Joao Goulart on April 1, 1964, and maintained close ties to Brazil's military rulers during the dictatorship.

Peter Kornbluh, director of the Brazil Documentation Project at George Washington University’s National Security Archive, which has been helping Brazil obtain US documents about state-sanctioned torture, singled out the seven-page cable and called it “one of the most detailed reports on torture techniques ever declassified by the US government.”

The cable was sent by the US Consul General in Rio de Janeiro and describes how “subversives” made up “mostly of university students” who opposed the military dictatorship were held indefinitely and subjected to “an intensive psychophysical system of duress designed to extract information without doing visible, lasting harm to the body.”

The same clinical descriptions used in the State Department cable could also be found in declassified CIA documents released in 2009, which basically said that the torture of “war on terror” prisoners would not and should not leave any noticeable marks.

A former CIA attorney noted in one document that if a detainee in US custody died, “you’re doing it wrong.” Brazil must have been doing it wrong, because the descriptions of the torture by police forces outlined in the State Department cable say detainees “suspected of being hardened terrorists” were subjected to “physical violence which sometimes cause death.”

“The hardened terrorist is mercilessly ‘squeezed,' it is said, for information through the use of the old, more physically brutal and violent forms of duress [redacted],” states the cable, which did not criticize the use of torture. “He is sometimes eliminated and his death may be reported in the press several days later as having occurred during a ‘shoot-out’ with the police while he was ‘attempting to escape.’ Many sources contend that the ‘shoot-out technique’ is being used increasingly by the police not only in Rio but throughout Brazil in order to deal with the public relations aspect of eliminating subversives. This technique is said to have been adopted… in order to obviate the death-by torture charges in the international press.”

Lower-ranking detainees who refused to “confess” were stripped naked and placed in a small dark room with a metal floor “through which electrical current is pulsated.”

“The shock felt by the individual, though reportedly light in intensity, is constant and eventually becomes almost impossible to withstand,” the cable says. “The suspect is then usually kept in the room for several hours. He may then be transferred to several other ‘special effects’ rooms in which devices are used to instill fear and physical discomfort.”

The release of documents about Brazil’s use of torture comes at a time when the US government is struggling to reconcile its own human rights abuses. For two years, the Senate Select Committee on Intelligence and the CIA have been battling over the integrity of a $50 million, 6,000-page report on the agency’s torture program.

The executive summary of the report, which the CIA finished declassifying and sent to the White House for review, says detainees in custody of the CIA were subjected to torture techniques that went beyond those authorized by Bush's Justice Department, and that CIA knowingly misled the White House, Congress, and the Justice Department about the intelligence value of the captives it was torturing.

But the full report will remain classified and the public will only be authorized to see a sanitized version of the study’s findings and conclusions. When that may happen is still unknown. The Obama administration claims release of the report could spark violence in the Middle East and endanger US troops, and steps are being taken to prepare for that, whatever they may be.

“The fact that the documents [about Brazil] contain harrowing details of sophisticated but no less barbaric forms of torture and state-sponsored murder in Brazil will certainly raise the historical comparison to the techniques that the CIA used that the US public are about to learn about,” Kornbluh told VICE News. “If we feel the horror of what Brazilian interrogators did in the 1970s, we presumably will feel the horror of what CIA interrogators did only a few years ago.”