 During Joseph's time in the Black Panther Party, he befriended Afeni Shakur, who was later one of his fellow defendants in the Panther 21 trial, and would act as Godfather to her son Tupac Shakur.In 1981, he was convicted for harboring a fugitive, Mutulu Shakur (Afeni's husband), who had taken part in the robbery of a Brink’s armored car in Rockland County, New York as part of an operation by members of the Black Liberation Army and the Weather Underground.For this, Joseph served 5 and a half years in Leavenworth State Penitentiary in Kansas, where he earned two college degrees and wrote his first play.