‘You can come in, but only because I’m not working,’ said Mary. ‘If I were busy, I’d ask you to leave. I’m a painter.’ Her eyes narrowed. ‘But you know that already. I’m sure you know all about me.’ In spite of what she’d said, she was still blocking the entrance to the house with her narrow body.

‘You didn’t let Chris Gibbs in,’ said Charlie. ‘You nearly didn’t let Simon Waterhouse in.’

‘Because I was working on a painting, one I stayed up all night to finish. As soon as I’ve got rid of you, I’ll be going to bed. Anyway, that’s why the song was on so loud, if you care: I was celebrating. Do you have a favourite song?’

It was ridiculous not to want to answer. ‘ “Trespass” by Limited Sympathy.’

‘The song that was on before—that’s mine.’

Charlie wasn’t going to ask again what it was. If you care. She didn’t.

‘ “Survivor” by Destiny’s Child,’ said Mary in a brittle voice, like a pupil forced to hand over a treasured forbidden item to her teacher. As she spoke, the lines on her face rearranged themselves, criss-crossing around her mouth. Charlie had heard that excessively thin people aged more severely than plumper ones, but even so . . . ‘I could tell you what I love about it, but I don’t suppose you’re interested. I suppose you’re one of those people who only puts on a CD if you’ve got guests for dinner, with the volume down so low that nobody can hear it.’

‘I don’t do that, actually,’ said Charlie. ‘I don’t rupture my neighbours’ eardrums, either.’

‘I told you: I was celebrating. Finishing a piece of work you’re happy with—it’s such a buzz. Like being able to fly. I wanted to reward myself, so I put on my favourite song and went round the corner to buy some smokes and peppermint tea. I put the volume up high so that I’d hear the song while I was in the shop.’ Mary smiled vaguely, a faraway look in her eyes, as if she was thinking back to something that had happened years ago.

Charlie’s skin prickled with apprehension. She thought of Ruth Bussey saying, ‘I’m frightened something’s going to happen. ’ ‘Could I see the painting?’ she asked. ‘The one you’ve just finished?’