The Riocentro bombing (Portuguese: Atentado do Riocentro) was an attempted terrorist attack that took place on the evening of 30 April 1981, during a May Day celebration concert at the Riocentro convention center in Rio de Janeiro, Brazil. The bombing, carried out by officers of the Brazilian Army, was a false flag operation intended to frame left-wing guerrillas as violent and thereby halting the country's transition towards democracy. It ended up having the opposite effect, accelerating the end of Brazil's military regime, in power since 1964. One of the perpetrators of the attack died, while the other was injured, from an accidental detonation of one of the bombs. A criminal inquiry from the time was inconclusive. There have been renewed investigations since 1999, one of which, conducted by the National Truth Commission, concluded that military authorities were responsible for the planning and execution of the bombing. Background In April 1964 a coup d'état overthrew elected president João Goulart and installed a military government that went on govern the country until 1985. The first president in this regime, General Humberto Castelo Branco, who represented a moderate wing of the Brazilian military, was sidelined in 1967 by hardline president Artur da Costa e Silva, his successor. In 1968 president Costa e Silva and his ministers passed the Institutional Act Number Five (AI-5), an executive order that, among other things, suspended the right to habeas corpus and allowed the military to shut down opponents of the regime through force and suspension of political rights. Under the regime an extensive national security network was established, composed of the National Intelligence Service (SNI) and the Center for Internal Defense Operations (DOI-CODI); the SNI was instrumental for the government to pursue a repression of opposition. The state DOI-CODI centers and the Center of Information of the Navy (CENIMAR) detained and tortured several regime dissidents as part of the Doctrine of National Security, a policy institutionalized by the army. The late 1970s and much of the 80s saw the rise of redemocratization movements throughout Latin America that sought to end the prevailing military regimes in the region. The democratic cause in Brazil and all of Latin America was in part aided by U.S. president Jimmy Carter's promotion of human rights in his foreign policy. In 1974 the newly-inaugurated Ernesto Geisel administration moved away from the authoritarian repression of president Emilio Garrastazu Medici's government, and towards a restoration