the north by their officers under the pretext of suppressing risings elsewhere in Spain. The First Infantry Regiment at Retiro had surrendered their barracks to government forces without opposition. Finally at the Getafe Air Base, rebels had been defeated by loyal troops after the death of an air force officer. This permitted flights to be made over the Montaña barracks the next day, initially to drop leaflets and then bombs. The communist-led Antifascist Worker and Peasant Militias formed five battalions that took an active part in the siege. One of these battalions became the renowned Fifth Regiment. 20 July On the morning of 20 July, two 75 mm guns commanded by a retired artillery officer Captain Orad, plus one 155 mm gun joined the siege. Also, a Breguet XIX warplane from the Cuatro Vientos Air Base bombed the barracks. At half past ten, one bomb wounded Fanjul and Serra. A few moments later some soldiers inside the barracks waved a white sheet from the windows apparently with the intention of surrendering. Against the orders of Lieutenant Moreno of the Assault Guards, who were leading the attack, the crowd ran forward but other defenders fired at them from the barracks with machine guns. This happened twice, killing or wounding numbers of people. Around noon, the crowd maddened by these incidents broke through the main gate. Some surrendering defenders were massacred by the crowd in the main courtyard, several being thrown from an upper gallery. Photographs show the courtyard littered with uniformed bodies. Orad and Arturo Barea both reported seeing a number of rebel officers who had gathered in a mess room and then shot themselves. At least some of the falangist and monarchist volunteers wearing civilian clothes were able to slip away in the confusion. Colonel Serra was among those killed immediately after the fall of the barracks. The wounded General Fanjul together with other surviving rebel officers, was detained in Madrid's Model Prison for trial. Of the 145 rebel officers who had been at the Montaña barracks, 98 died in the fighting, were killed after surrender, committed suicide, or were subsequently executed. Some of the garrison were reportedly killed by attackers with axes, knives and mallets. Total losses among the defenders are estimated at between 200 and 1000 dead while the casualties among the attacking forces appear to have been significantly lighter. The rifle bolts and ammunition that had been