Some of the decades' most infamous labor disputes occurred in Colorado. In 1927, Mexican-American coal miners participated in a bloody coal strike in Colorado, walking out under the banner of the Industrial Workers of the World. Mexican-Americans in the southeastern part of the state, particularly from the Walsenburg, Pueblo, and Trinidad areas, took leadership roles in the 1927 strike, protesting for better and safer working conditions. Some mine owners in other parts of the state retaliated against the striking miners by refusing to hire any Mexican or Mexican American in their mines. In Walsenburg and Trinidad, the mine owners went to more extreme measures to stymie the protests. Mine owners hired armed men to attack the IWW's Trinidad hall and Walsenburg branch halls. In Walsenburg, the men used a machine gun to attack the IWW hall, ultimately killing two union strikers, Salastino Martinez (age 15) and Klementz Chavez (age 41), on January 12, 1928. Josephine Roche, president of the Rocky Mountain Fuel Company, invited the United Mine Workers of America to unionize her mines, so as to meet some of the strikers' demands without alienating other mine owners, who remained strongly opposed to the IWW.