Cordelia shrugged. “I haven’t anything to say that won’t keep. No flash of genius that will vanish for ever if I don’t give it shape and form immediately. Let’s see her and have done for today. Then we can go and have dinner somewhere and sort out what we’ve got so far.”

“That should see us through the aperitifs,” said Lindsay wryly. “Now, where do we find her?”

“It’s just down the corridor here. I checked with Paddy’s list.” Cordelia led the way to Sarah’s room and knocked. After a short pause a low voice invited them in.

Sarah Cartwright’s room was furnished exactly as Caroline’s, and had a splendid view of the trees that cut Longnor House off from the bleak moorland behind. But there were few of the personal touches that made Caroline’s room so individual. The walls were bare except for a large black and white framed photograph of a gymnast on the beam, who Cordelia identified as Nellie Kim, the Russian Olympic medallist. The books were all school textbooks except for several on gymnastics, and the desk was almost pathologically neat. On it there was one small framed wedding photo. The man was clearly a younger version of James Cartwright. Lindsay assumed the dark-haired, vivacious-looking woman by his side was Sarah’s mother.

The girl was sitting cross-legged on her bed, reading a newspaper. As they entered, she folded it carefully and put it down. She had dark brown hair cut short and neat with a straight, heavy fringe, contrasting with pale skin untouched by the ravages of adolescence. She had an air of extreme self-possession, but her dark eyes were watchful. Unlike her father, she seemed prepared to let other people make the running. She looked inquiringly at them.

Lindsay felt instantly uncomfortable, as if she were an unwelcome intruder on someone else’s private territory. “I’m sorry to butt in on you,” she said, “but I wondered if perhaps you could help us.” Sarah said nothing. Lindsay glanced at Cordelia in a mute appeal for help.

Cordelia took up the hard job of communication. “Miss Overton has asked us to see if we can uncover anything that might establish Miss Callaghan’s innocence. We’ve been talking to a lot of people in the hope that they might be able to come up with something to help and, basically, you’re next on the list.”