 At the organizational level, the PRT would function as the political and military command center of the armed faction of ERP, with Santucho acting as secretary general of the former and commanding officer of the latter.ERP would become during the 1970s the largest guerrilla organization in South America, and a prime example in Argentina of the "foquismo" tactic associated with Che Guevara.Santucho was arrested in August 1971 in the Argentine city of Cordoba and transferred to the Villa Devoto Prison in Buenos Aires.