02 August 1968,
ETA killed Meliton Manzanas at the door of his house in Irun. He was head of the Gipuzkoa Social Political Brigade and worked for Gestapo in occupied France, passing the lists of Jews to the Nazis.
This Donostia was known for ruthlessly torturing many people. Following the death of Txabi Etxebarrieta by the police, the armed organization wanted to demonstrate its responsiveness and chose a symbol of Franco with direct responsibility in the repression. It was the first ETA murder previously prepared.
It caused a political earthquake and a repressive response. Within four days of the exceptional situation of the Franco regime, 300 persons were arrested.
Source:
Emilio Lopez Adam, Armed Struggle in the Basque Country (1967-2011) (May).