‘He never told me,’ Anne said. ‘William had always been such a happy boy and of course I knew something was wrong. He’d changed. But I thought it was down to the pressure of starting at university. He’d never lived away from home before. And of course he’d had to borrow the money to pay the tuition fees and that was preying on his mind. It was only after he died that the police found all the evidence on his computer. He’d gone through his savings and he’d maxed out all his credit cards. And he’d sold things.’ Until now, Anne had been strangely dispassionate, explaining her past history as if it was unconnected to her. But for the first time her voice cracked. ‘He’d sold the watch we’d given him for his eighteenth birthday and the laptop when he’d started university. He’d sold his clothes. All the time, he was getting more and more desperate, but he kept on playing, spinning the wheel in the hope that he would make everything right. And when it got to be too much, he took an overdose of paracetamol. That was the drug that killed him.’

Hawthorne was accusing Anne Cleary of murder, and I had been witness to two shocking deaths. But I felt only pity for her. ‘I’m so sorry,’ I said.

She stared at me. ‘I don’t want your pity. I made the decision to commit a crime. It was a dreadful thing to do and I always expected to pay the full price.’ Anne turned back to Hawthorne.

‘Two crimes,’ Hawthorne said. ‘You also killed Helen le Mesurier.’

‘Yes.’

Anne Cleary hadn’t even tried to deny it. She was sitting very still. I was aware of the hollow ticking of the clock on the mantelpiece. I wanted to get up and silence the wretched thing.

‘When I heard about Derek Abbott, I thought that might be the end of it as far as I was concerned,’ she said. ‘But if you’ve come here to judge me, you’re too late. My judgement has already been made.’

‘It’s not just you, Anne. You weren’t alone.’

That jolted her. ‘Yes, I was.’

‘Do you really think you can lie to me? Even now? You couldn’t have tied Charles le Mesurier to that chair without help, even if you had whacked him with a rock first. You also needed someone to persuade Helen le Mesurier to walk into that cave where you were waiting for her. All of this was carefully planned. And not just by you.’

‘I killed both those people. I will pay for it.’ She looked at him with a growing desperation. ‘What more do you want, Mr Hawthorne?’