In 1976 the body of Anna Mae Aquash, an American Indian luminary, was found frozen in the Badlands of South Dakota--or so the FBI said. After a suspicious autopsy and a rushed burial, friends had Aquash exhumed and found a .32-caliber bullet in her skull. Using this scandal as a point of departure, The Unquiet Grave opens a tunnel into the dark side of the FBI and its subversion of American Indian activists. But the book also discovers things the...