At 8.16 am on the morning of 21 June 1993, the terrorist organisation ETA set off a car bomb containing 40 kilograms of explosives as a military van was travelling along Calle Joaquín Costa, at the corner with Calle López de Hoyos. The vehicle, with a civilian driver at the wheel, was taking six senior army officers to the headquarters of the Joint General Staff and the Higher Centre for National Defence Studies, both on Calle Vitruvius. The van took the full impact of the blast and was enveloped in flames. Seven of its occupants were killed: Lieutenant-Colonel Javier Baró Díaz de Figueroa of the army; Lieutenant-Colonel José Alberto Carretero Sogel of the air force; Staff Sergeant José Manuel Calvo Alonso of the navy; Lieutenant-Colonel Fidel Dávila Garijo of the army; Commander Domingo Olivo Esparzay of the navy; Pedro Robles López, a civilian working for the Ministry of Defence who was driving the vehicle; and Lieutenant-Colonel Juan Romero Álvarez of the Air Force. A further forty people were seriously wounded, including three children.
Pedro Robles López, aged 57, from Santander, was a civilian functionary working in the Ministry of Defence. He was married and had three children. He normally worked afternoons, but had switched to double shifts to earn some extra money for his family.