What she saw made her gasp and turn away, her hand to her mouth. Lindsay caught hold of her and held her tightly. She looked over Cordelia’s shoulder and took in a vision of absolute horror. She said harshly. “We mustn’t touch anything.” Lindsay gently released Cordelia and steered her on to the landing before forcing herself across the threshold. She quickly glanced around, feeling her chest tighten, then spoke commandingly to Cordelia. “Go down to Paddy’s room. Get Pamela Overton here and call the police.” Cordelia stood numbly, seeming not to have heard. “Do it now,” Lindsay cried. Cordelia shook herself and stumbled down the corridor.

Left alone, Lindsay somehow steeled herself to look at the appalling scene inside the room. She desperately wanted to see if there was anything obvious to explain the significance of what had happened there.

Sarah Cartwright—or what remained of her—sprawled half on the floor and half on the bed. Her left arm was slashed almost to the bone at wrist and elbow; her right arm had a matching cut, though far less deep, at the wrist. A sheath knife lay on the floor. She had obviously cut herself leaning over the washbasin, for it was filled with a grisly mixture of blood and water. As consciousness had slipped away, she had fallen back and her blood had splashed the walls and soaked the carpet and bed. Lindsay badly wanted to be sick, but from somewhere came the strength to carry on her examination. She moved across to the desk, careful to avoid the blood.

On the top of the desk was a single sheet of foolscap paper, covered in neat handwriting. It was what she had half-expected to find. Across the top was written in block capitals, “To anyone who has an interest in the death of Lorna Smith-Couper.”

The message continued,

I want to say first of all that I am sorry for all the trouble that I have caused, especially to my father, Miss Callaghan, and the school. At the time, I thought I was doing the best possible thing and I did not think anything could be proved. I did not mean to incriminate Miss Callaghan.

I killed Lorna Smith-Couper. I fetched scaffolding from the squash courts and used it to climb from the kitchen roof to the music room. I climbed in the window and strangled her while she was playing. I knew she would be there because Miss Callaghan told me that morning when we were there together. I did it for my father. I wanted him to get the school playing fields to save his business, especially now I know what people at the school really think of me.