Born in the Brazilian city of São Paulo on 4th November 1914, Edmur Péricles Camargo, also known as "Gauchão", had been the leader of a small guerrilla group called M3G (Marx, Mao, Marighella, and Guevara) which operated between 1969 and 1970 in Porto Alegre city in the state of Rio Grande do Sul. 

Edmur became a member of the Brazilian Communist Party (PCB) in 1944 and he started to work at the Fishermen's Union (SAPERJ) in Rio de Janeiro. By 1952, he was in charge of a newsletter called A Tribuna, which was the PCB's official press outlet in Porto Alegre city. Following the 1964 coup d'état in Brazil, Edmur sought refuge in Uruguay, where he received training from the local guerrilla group, the Movimiento de Liberación Nacional- Tupamaros (National Liberation Movement, MLN-T). He returned to Brazil in 1967.

Following the disintegration of the PCB, Edmur helped Carlos Marighella to form the São Paulo Communist Association. He later joined the Brazilian armed guerrilla organisation, the Ação Libertadora Nacional (National Liberation Action, ALN). However, Edmur held different opinions from the ALN's leader in terms of his strategy toward the revolutionary struggle. He, therefore, decided to leave the organisation and instead went to Porto Alegre in April 1969 to organise the M3G.

Edmur Camargo was arrested in 1970 and expelled from the country in January 1971 following the kidnapping of the Swiss Ambassador in Brazil, Giovanni Enrique Bucher. Edmur was one of the 70 political prisoners who were captured in Brazil by the Vanguarda Popular Revolucionária (Popular Revolutionary, Vanguard) and released in exchange for the diplomat. Camargo headed for Chile with other Brazilian deportees.

On 16th July 1971, Camargo moved to Montevideo aged 57 to undergo treatment on his eyes after the torture he suffered had damaged his sight. He travelled with false documents under the name of 'Enrique Villaça'.

The previous day, information related to his journey had filtered through to the Brazilian embassies in Santiago, Montevideo, and Buenos Aires. The Brazilian National Truth Commission found that documentation from the intelligence network that monitored Brazilian exiles from abroad, the Centro de Informações do Exterior (Centre of Information from Abroad, CIEX), indicated that the Brazilian Embassy in Chile's naval attaché had been tipped off by an Argentine agent. The Argentine officer had infiltrated the airline, LAN Chile during Camargo's flight. Having confirmed that the aeroplane that was heading for Uruguay was going to stop over in Argentina, the military attaché in Montevideo travelled to Buenos Aires. Meanwhile, his counterpart in Buenos Aires verified the possibility that the Argentine authorities had arrested Camargo and handed him over to the Brazilians.

On 16th June 1971, agents from the Policía Federal Argentina (Argentine Federal Police, PFA) removed Camargo by force from the LAN plane in front of the other passengers at the Ezeiza International Airport in Buenos Aires.

During the early hours of 17th June, Camargo was escorted by the Airforce Attaché Miguel Cunha Lana and the CIEX director Paulo Sérgio Nery. He was returned to Rio de Janeiro in an aeroplane belonging to the Brazilian Airforce that had travelled to Buenos Aires especially to transport him. He was never seen again.

Weeks later, in August 1971, Brazilian refugees who were living in Chile openly denounced Camargo's disappearance. Camargo had not been in contact with any of his friends since the date of his alleged return to Chile in July. The rumour spread among the Brazilian exile communities that the Argentine and Brazilian police had kidnapped him and handed him over to the Brazilian dictatorship.

During early 1972, Brazilian refugees started to suggest that the Airforce Attaché of Buenos Aires' Brazilian Embassy was responsible for Camargo's disappearance. The Brazilian refugee, Joaquim Pires Cerveira had met a similar fate when he was kidnapped in Buenos Aires and secretly transferred to Brazil at the end of 1973. He managed to obtain the list of passengers on the LAN Chile flight confirming that the pilot had authorised Camargo's forced disembarkment at Ezeiza Airport.