He also carried out various social service activities for the benefit of the miners' families. Cuba Sarabia joined the Communist Party of Bolivia (PCB) but resigned from it in 1965 to become a member of the Bolivian Marxist–Leninist Party which favored armed struggle. When he urged that group to put its principles into practice, he was expelled from it along with Moisés Guevara.[expelled] It was Moisés Guevara who brought him into Che Guevara's Ñancahuazú guerrilla group in March 1967.[1]