Violence was not uncommon. The most striking event was the 1977 Atocha massacre, where five people working for Comisiones Obreras (a trade union affiliated to the Communist Party) were murdered by right-wing extremists. There was also violence from left-wing groups, like ETA (which continued to campaign violently for the independence of the Basque Country) or new groups like GRAPO, a Maoist group, or MPAIAC, a Canarian independence group.