04 December 1970,
The young Roberto Pérez Jauregi was shot by the Spanish police in a protest against the Burgese trials in Eibar. He was a member of the International Communist Party of Spain (PCEi), near Maoism, which would later become PTE. He died four days later. No one has ever been tried for murder.
Source:
Joseba Zabraise, Names to remember. (Basque Memory Foundation).