It was almost dusk when Miller turned the Cooper in through the gates of the house in Grange Avenue and braked to a halt at the bottom of the steps leading up to the front door. It had been a long day and he was so tired that he sat at the wheel for a moment before getting out.

When he rang the bell, the door was opened by Jenny, the young maid, and her eyes were red and swollen from weeping. ‘Sergeant Miller,’ she said. ‘You’d better come in.’

‘There was a message for me at Headquarters,’ Miller said. ‘Apparently Colonel Craig called at the mortuary to view his daughter’s body. I understand he’d like to see me.’

‘The Colonel and Miss Harriet are out walking in the garden,’ Jenny said. ‘I’ll get him for you.’

‘That’s all right,’ Miller told her. ‘I’ll find him for myself.’

It was cold in the garden and rooks cawed uneasily in the bare branches of the beech trees as he crossed the lawn already damp with the evening dew. Somewhere there was a low murmur of voices above the rattle of a small stream over stones and then a familiar voice called to him on the quiet air. ‘Over here, Sergeant Miller.’

Harriet Craig leaned against the rail of a tiny rustic bridge. The man who stood with her was perhaps a shade under six feet in height with iron grey hair cut close to his skull.

The eyes were very calm above high cheekbones. For a moment they considered Miller and then he held out his hand. ‘It was good of you to come so quickly.’

There was an extraordinary impression of vitality about him, of controlled force that Miller found strangely disturbing. He must have been at least forty-eight or -nine and yet he carried himself with the easy confidence of a man half his age.

‘Your message said that you’d like to talk things over with me,’ Miller said. ‘I’ll be happy to help in any way I can.’

‘I’ve seen your Superintendent Grant,’ Colonel Craig said. ‘He gave me as comprehensive a report as he could, but felt that the full details would be better coming from you.’ He hesitated and then went on, ‘I believe Harriet gave you some indication of the trouble we were having with Joanna.’

‘That’s right.’

‘I’ve been given to understand that she’d become addicted to the drug heroin.’

‘Which explains what otherwise would have been her completely inexplicable change in character,’ Miller told him. ‘You must understand that heroin produces a feeling of well-being and buoyancy, but in between fixes an addict is sick, unwell and has only one thought in mind – to get another fix. They become paranoid, irritable, subject to extremes of emotion.’

‘And that’s what happened to Joanna?’