The Cypress Hills of what would later become southwestern Saskatchewan and southeastern Alberta were a traditional winter hunting area for several of the Plains tribes and were considered a place of spiritual significance. As a gathering place of Natives, the hills also attracted the attention of traders and hunters, many of them Americans from Montana who traded for wolf pelts and carried liquor as a trade good. During the winter of 1873, a group of wolf traders, disgruntled after having had some horses stolen from them in Montana, accused a group of Assiniboine encamped in the Cypress Hills of harbouring the stolen horses. Fuelled by illicit liquor, tempers flared, and, in the ensuing debacle, some 20 to 30 Assiniboine people were murdered. News of the Cypress Hills Massacre led to calls for the enforcement of Canadian justice on the Plains to avoid the bloody experience of American frontier expansion, and the Canadian government responded by accelerating the organization of the North-West Mounted Police. For the Plains tribes, the massacre reinforced a commitment to deal constructively with the Canadian authorities in an effort to preserve their culture from the onslaught of further frontier warfare. The tenacity of the N-WMP in pursuing the Cypress Hills perpetrators helped to establish good early relations between the force and the Native peoples, despite the fact that those eventually charged with the crime were acquitted.