José Miguel Moros Peña was working on a construction site and was killed as he was about to start up a drilling machine. A bomb that had been placed under the machine exploded, causing him very serious injuries and severing his left forearm. Despite undergoing surgery at Cruces Hospital in Barakaldo, he died some months later as a result of the attack.
The Municipal Police in Santurce had received a bomb warning the night before, which had been passed on to the National Police and the Municipal Police of Portugalete. However, they doubted the veracity of the information that the bomb had been planted on the construction site.