1892 Coeur d''Alene labor strike Wikipedia
The Coeur d''Alene, Ido, labor strike of 1892 erupted in violence when labor union miners discovered they had been infiltrated by a Pinkerton agent who had routinely provided union information to the mine owners. The response to that violence, disastrous for the local miners'' union, became the primary motivation for the formation of the Western Federation of Miners (WFM) the following year.