The victim was kidnapped on 5 October, when he was leaving his home shortly before 8.00 am to go to work at the Military Government in Bilbao. He never reached work. The group did not demand a ransom, but instead called for the suspension of a trial against members of the group who had been charged with assaulting an army barracks in the Catalan town of Berga two years earlier.
Between the kidnap and the eventual murder, the terrorists played cat and mouse with the media, demanding that they read out the full text of their communiqués, which were full of radical propaganda. At the same time, the soldier’s family anxiously pleaded with the group to release him.
On 13 October the group gave 36 hours for their statement to be read on the 3 pm and 8.30 pm television news. The ultimatum was accompanied by two photographs of the kidnapped man, in which Martín Barrios was shown with several days’ stubble in front of a Basque flag and posters and stickers of the group. Under pressure, TVE broadcast part of the script on 13th, declaring that it would only read the full text of the statement when the captain was released. The body of the captain of the Pharmaceutical Division was found gagged with a bullet wound in the right temple, in a wooded area near Bilbao. No one has ever been charged for the crime.