Payment In Blood by Elizabeth George

In a secluded Scottish manor, a theatrical retreat turns deadly when a playwright is found murdered, her body discovered with a dagger in her chest. As Detective Inspector Thomas Lynley and his partner, Sergeant Barbara Havers, delve into the tangled web of relationships and hidden secrets among the guests, they uncover a world of jealousy, betrayal, and ambition. With each suspect harboring their own motives and alibis, Lynley and Havers must navigate the complexities of human nature to unmask the killer before they strike again.