From Doon with Death (Inspector Wexford) by Ruth Rendell

Ruth Rendell’s debut work of crime fiction is also the first novel to feature the classic crime-solving detective, Chief Inspector Wexford. No one believed Mr Parsons’ fears for his missing wife. Until two days later she was discovered in the woods, her face swollen and her clothes damply clinging to her lifeless body. With no useful witnesses and a victim known only for her mundane life, Chief Inspector Wexford has just one clue: a lipstick found at the scene. To find the killer, Wexford must first discover a motive. Because what he can’t understand is how such an unassuming woman became the victim of such a passionate and violent crime.