Death Comes as the End by Agatha Christie

In this startling historical mystery, unique in the author's canon, Agatha Christie presents the puzzle of a deadly mystery at the heart of a dissonant family in ancient Egypt. Imhotep, wealthy landowner and priest of Thebes, has outraged his sons and daughters by bringing a beautiful concubine into their fold. And the manipulative Nofret has already set about a plan to usurp her rivals' rightful legacies. When her lifeless body is discovered at the foot of a cliff, Imhotep's own flesh and blood become the apparent conspirators in her shocking murder. But vengeance and greed may not be the only motives...