Prophecy Rock (Hardcover, Turtleback School & Library ed.)

Will Lansa, raised by his white mother in Aspen, is spending the summer on the Hopi reservation with his father, the tribal police chief. The chief is investigating the murder of a man found near a sacred place. Some suspect it's the work of a "powaqu", a powerful witch. Will's own investigation finds him caught up in ancient prophecies and mystical visions that suddenly place his life in jeopardy.