Again there was quiet in the room. It wasn’t easy for Lindsay to become the interrogatory machine, but she stifled her feelings and continued remorselessly. “You went for a walk with her on the morning of the day she died, didn’t you?” she demanded.

Swiftly, Margaret’s head came up. There was no mistaking the fear now. “No!” she replied sharply. “No, I didn’t go for a walk with her.”

“You were with her in the gardens on Saturday morning and you were arguing.”

“That’s not true.”

Lindsay slipped the photograph from her handbag and offered it to the music mistress, who glanced at it, then rose to her feet and walked to her desk, where she collapsed in her chair.

Lindsay spoke gently. “I was up on the hillside taking some photographs. The red sweater you were wearing caught my eye. I haven’t shown these to the police yet. There seemed to me to be little reason to do so. But now Paddy has been arrested, I think I might have to go to the police with them. Unless I am convinced that they have nothing to do with the murder and would therefore serve no purpose in helping Paddy.”

Margaret Macdonald looked Lindsay straight in the eye. Her fear had been replaced by resignation. She shrugged, then said bitterly, “After all, why not? If anyone can understand it, maybe you two can. They say it takes one to know one.”

Lindsay kept her eyes on the teacher, but on the edge of her vision she was aware of Cordelia turning away, whether from sympathy or embarrassment she could not tell. Margaret sighed deeply. “I’ve never told anyone this, and I hoped I would never have to.

“Fifteen years ago, Lorna was a seventeen-year-old with a blinding and brilliant gift. The cello was my own instrument, and though I could never play like she did, I’m a good teacher. I had experience and so much enthusiasm to pass on. She wanted to absorb all she could from me, and I was happy to show her every secret.

“We spent hours together, practicing, listening to music, or just talking. I had always known I was different from most of my friends. I only ever felt emotionally attracted to my own sex. It’s ironic really—everyone assumes that it was my love of music and teaching that made me choose this life. But for me it seemed the only option because it was a life I could lose myself in.