At around six o’clock in the evening three members of the CAA in a Renault 12, opened fire with machine guns on the Civil Guard Barracks in Arechavaleta (Guipúzcoa). There were no casualties. The officers inside the barracks fought off the attack and the terrorists made their escape. The civil guards pursued them as far as Mondragon, where the terrorists were slowed by heavy traffic.
A gun fight commenced between the terrorists, the Civil Guard patrol that was chasing them and some reinforcements who arrived on the scene. Emilia Larrea was killed during this exchange of shots.