Molly shook her head.

“By then he would have convinced himself that he had found it, that he hadn’t killed Tom, that his voices had been the killer’s. Last night he kept saying: ‘They killed Tom.’”

George continued with a steady, detached voice, as if he hoped that an explanation of the facts would calm Molly, and that he could replace some of the emotion with reason:

“When Adam came for a meal with us, I told him that somebody had seen the murderer on the marsh track with Tom’s body. Perhaps he thought that we suspected him, or at least that we had a description of the murderer. He felt that he had to divert attention away from himself.”

“So he wasn’t pushed down the well,” Tina said. She was angry. “I was so sorry for him. He seemed so frightened. I thought he needed me to protect him. And it was all acting. He climbed down.”

“That’s not possible.” Rob was adamant. “ I can’t believe it. You said that he was terrified when they got him up, and he couldn’t have climbed down there. Not without a rope.”

“He used a rope,” George said. “ His father was quite famous as a mountaineer, and he used to take Adam with him, when Adam was younger. There’s a mark in the wood of one of the uprights on the windmill. It puzzled me at the time. It was caused by the rope biting into the wood. Adam must have doubled it around the post, so that he could pull it after him. Then he would have thrown it down into the well. Of course he was terrified. It was dark down there. Perhaps he panicked when everyone arrived at the party, but nobody heard him. I presume that by then he had pulled down the rope and thrown it away. It would have been impossible for him to climb out on his own.

“If you remember, we thought it strange that he’d left his binoculars and telescope at home that day. I should have realized then that the whole thing was planned. He was afraid of losing them or damaging them. But I liked him. It stopped me thinking straight.”

George remembered that night and the white, sobbing boy. If only he had known, then. He knew that the boy had been ready to confide in him. If only he had said the right words, had had the ability to inspire a little trust. But then nothing, really, would have been very different. He had a sudden vision then of the remand centre where Dennis Shawcroft had been held, the long walls and the smell and the uniforms. The hospital would not be very different.

“But why me?” Sally said suddenly. “I don’t understand what he had against me!”

She coddled Barnaby close to her in a fierce, involuntary gesture.

“Your involvement in it confused me all the way through. It was an unhappy coincidence, but it was all, in a way, provoked by Tom, who tried too hard with people, who couldn’t relax with them. You couldn’t tell me about Peter because you were frightened for him, and you couldn’t explain why you were so obliged to Tom because Peter was involved. Bernard Cranshaw wrote unpleasant letters to you because he hated Tom, and because he was jealous of him, and, in a way, of you. You both represented a freedom which he could never attain. But he seemed to me too weak to hurt Tom. Even when he was trying to scare the birders off the marsh he never really meant to hurt them. When he tried to hurt his mother he only bruised her. And his hatred for you and Tom was too close to love for him to contemplate doing you any real harm.