Communist Party of Brazil
In 1964, when the military instored their dictatorship, Pinheiro was admitted to Law School at the State University of Guanabara (currently UERJ). There, he joined the MR-8, then the most important urban guerrilla in Brazil, and connected to the Communist Party of Brazil. Again he was elected as chair of the student board ("Centro Acadêmico Luiz Carpenter").