A junta in Burgos proved unable to set overall strategy ; thus , Franco was chosen commander-in-chief at a meeting of ranking generals on September 21 . Mola continued to command the Army of the North and led an unsuccessful effort to take Madrid in October . In a radio address , he described Nationalist sympathizers in the city as a " fifth column " that supplemented his four military columns . The Republican government then proceeded to carry out the mass execution of as many as 2,000 suspected civilian and military supporters of the Nationalists . What was later known as the Paracuellos massacres crushed any potential fifth column
Paracuellos massacres
Paracuellos massacres
Emilio Mola