But he began to flounder, unsure what question he could ask her. Luckily, she took pity on him, and turned to mount the steps again, back into the cooling breeze.

‘John Casey phoned me,’ she said. ‘He keeps me up to date with anything relating to the hall. So I know about your visit there.’

‘Ah. I see.’

It was a relief to have the mystery explained. He should have guessed that Casey would have talked to her. But Mrs Chadwick had manipulated him so expertly that he hadn’t thought of the obvious.

‘But I can assure you that whoever left white chrysanthemums for Fair Flora, it wasn’t me,’ she said. ‘That’s what you came to ask, isn’t it?’

‘Yes.’

‘I haven’t been back to visit the hall since we left, two years ago. I don’t want to see it empty and abandoned, the furniture sheeted up like a mausoleum. I’m happy to leave everything in Mr Casey’s hands. The place doesn’t belong to me, you know. It reverted to the Devonshire Trust on my father’s death.’

‘Yes, I’m aware of that.’

‘So I have no claim on it, other than an emotional one.’

Madeleine Chadwick stopped by the rose bush again. She couldn’t seem to keep her hands off the deep-red blooms. Their petals were a little less damp now as they moved slowly in the breeze, but their colour was so dark that they looked almost black as they turned away from the sun.

‘John Casey told me that you and your colleague were particularly interested in the crypt,’ she said. ‘The bone collection.’

‘Yes.’

‘Well, the Alder Hall bones are centuries old. Surely they’re of no interest to our busy present-day police force. So I’m surmising there must be rather more recent bones somewhere that you’re looking for. Human remains, a victim of violence?’

‘It’s possible,’ said Cooper. ‘I can’t say any more than that.’

She stroked the petals of the rose, releasing a rich scent, like port wine.

‘Black Prince,’ she said. ‘Do you know anything about roses?’

‘I’m afraid not.’

‘Roses are very remarkable things. No wonder they’ve been revered so much through the millennia. People have regarded them with awe and reverence – and quite rightly. The plant itself isn’t very prepossessing, is it? Rather ugly, in fact. And it has these sharp, cruel spikes that can draw blood in an instant. Yet suddenly, at the right time of year, this plant blooms into the most exquisite flowers, and a delightful scent fills the air. It’s magical and mystical. It’s a symbol of the triumph of good over evil. The idea should interest you, as a police officer.’

Cooper nodded, but said nothing. He felt ashamed of the cynical thoughts that sprang into his mind.