 In 1909, he was elected mayor of Comitán.In 1912, Leopoldo Gout and he ran for a seat in the Senate (Domínguez as substitute senator); when Gout died, Domínguez replaced him.In 1913 he gave a speech in Congress against the dictator Victoriano Huerta and as a result he was murdered in Mexico City by Gilberto Márquez, Alberto Quiroz, José Hernández Ramírez, Gabriel Huerta, and Dr Aureliano Urrutia who chopped off Domínguez's tongue.