The RMCP stands for Royal Canadian Mounted Police. The police represent one way white society controls the First Nation people, the Kwakiutl.
For example, when the tribe wants to bury a very young boy who has drowned, they have to wait to get a death certificate from the RMCP. It takes the RMCP, which is stationed five hours away, ten days to send someone. The officer comes because it is a beautiful day and because he can bring his girlfriend. When he arrives, this young policeman, Constable Pearson, is rude. He is "loud and angry" with the natives because the body of the boy has been moved, rather than being left where he died. He demands an autopsy, but when he is shown the badly decomposed corpse, he gets sick, quickly signs the death certificate, and leaves.
Pearson represents the arrogance, disregard, and lack of understanding the authorities often have for the native people under their control, and his interaction with the tribe gives the new vicar, Mark Brian, insights into what they endure.
In another interaction with the RCMP, Mark learns from Keetah that she is concerned at not hearing from her sister, who left several months ago. Mark is able to report her missing. The RCMP do promise to search for her. In such ways, interspersed throughout the novel, the lives of the native people and the white authorities intersect.