The first charges brought against an army officer over crimes committed during the Brazil's 1964-1985 military dictatorship were dismissed by a Brazilian judge, dealing a blow to rights groups and victims' families.
Prosecutors brought charges in the last few days against Sebastião Rodrigues de Moura, best known as colonel Curió, 77, who commanded troops they say kidnapped and tortured five members of the Araguaia guerrilla movement in the Amazon, which was fighting to impose communism.
Human rights groups had applauded the charges as a "landmark step for accountability in Brazil," which critics say has taken only timid steps to deal with that dark chapter in its history. The fate of the five and several hundred others has never been discovered.
Prosecutors argued the kidnapping of the five was not covered by a 1979 amnesty law because they were not found and the case never closed. The prosecution argument heeded a 2010 decision by the Inter-American Court of Human Rights that Brazil must investigate those kidnappings and punish the perpetrators.
In dismissing the charges, Federal Judge João Cesar Matos argued they were covered by the amnesty law.
"Pretending that you can skirt around the amnesty law to reopen the debate over military dictatorship-era crimes ... disregards the historical circumstances which, in a great effort of national reconciliation, led to its implementation," the judge said in a statement on the Federal Justice website of Para state.
The judge added that even if he accepted the case, the legal time limit for a sentence to be given had passed.
Federal prosecutors in Pará state said they would appeal the judge's decision.
The accused colonel was a notorious figure from the dictatorship period that began after a military coup. He took over the running of the region in the Amazon where his troops were stationed and earned a fortune overseeing artisanal, or small, independent mining.
The judge's decision came on the day Defense Minister Celso Amorim called for the powers of a recently established truth commission to be expanded to enable it to investigate all the wrongdoings of the era.
Brazil's military dictatorship was less murderous than those in Argentina and Chile, but the country's leadership has been criticized for not doing more to investigate the violent acts committed and mete out punishment to those responsible.
About 475 people are estimated to have been killed or have disappeared during the dictatorship.
The issue is also a delicate one for Dilma Rousseff, Brazil's first woman president, who was herself a left-wing combatant during the dictatorship, subjected to torture at the hands of the military and imprisoned.
Rousseff has been careful to avoid creating the perception she is out to avenge the wrongs she suffered.
There is strong resistance against repealing the law among the military, many of whose dictatorship-era officers have yet to retire and argue the military saved Brazil from a communist revolution.