Los Justicieros, "The Avengers", is an anarchist paramilitary group created in 1920 in San Sebastián, Basque Region. The group was created by Buenaventura Durruti, Suberviola, Ruiz, Aldabatrecu and Marcelino del Campo among others. In 1921, during the inauguration of the Great Kursaal in San Sebastian, members of this group attempted unsuccessfully to assassinate King Alfonso XIII.
References
Los Justicieros Wikipedia(Text) CC BY-SA