In 1950 , the SACP was banned and both First and Slovo were listed as communists under the Suppression of Communism Act and could not be quoted or attend public gatherings in South Africa . He became active in the South African Congress of Democrats ( an ally of the ANC as part of the Congress Alliance ) and was a delegate to the June 1955 Congress of the People organised by the ANC and Indian , Coloured and white organisations at Kliptown near Johannesburg , that drew up the Freedom Charter . He was arrested and detained for two months during the Treason Trial of 1956 . Charges against him were dropped in 1958 . He was later arrested for six months during the State of Emergency declared after the Sharpeville massacre in 1960
Sharpeville massacre
Sharpeville massacre
Joe Slovo