ETA terrorists Domingo Troitiño, Josefa Mercedes Ernaga Esnoz and Rafael Caride Simón had received orders to carry out a series of attacks against French-owned or joint Hispano-French companies. Acting on these directives, they decided to plant an explosive device at the Hipercor shopping centre on Avenida Meridiana, Barcelona. Their intention was to cause as much damage as possible. They decided that it would be better for the explosion to go off during the day, during commercial opening hours.
Having placed twenty-seven kilograms of ammonal and two hundred litres of incendiary fluid, glue and soap flakes in a vehicle and setting the timer to go off at 4 pm, two of the terrorists left the car bomb in the second basement of the Hipercor car park. Shortly after 3 pm, Domingo Troitiño made three telephone calls: one to Barcelona Municipal Police, another to the shopping centre itself and a third to the newspaper Avui. Saying he was speaking on behalf of ETA he gave a location for the bomb, which he said would explode between 3.30 and 3.40 pm. Neither the police who came to the scene nor Hipercor’s own security service succeeded in locating the device. Eventually they decided that it was a false alarm and there was no need to clear the building. The car bomb exploded at 4.08 pm.
The explosion spread from the second basement to the first, which contained the food hall. According to a judgement from Section 1 of the National Court (Judgement 49/1989), the ball of flame burned people in its path and generated an enormous quantity of toxic fumes, suffocating all those in its range. Various people received hideous burns and injuries in the attack. In the darkness caused by the black smoke they were unable to escape and because of the composition of the explosives, the incendiary materials stuck to their bodies, making it impossible to shake them off or put them out, since the material self-combusted without requiring oxygen.
Matilde Martínez Domínguez, who was studying to be an engineer and draughtsperson at an academy in Barcelona, had gone to Hipercor on Avinguda Meridiana in Barcelona to buy some clothes. The car bomb went off when she was in the mall.