‘No, it’s you I want,’ Charlie told her.

‘Then I know why.’ The response was smooth and instantaneous. ‘You’re here to ask me about a man I don’t know. A man called Aidan Seed. DC Christopher Gibbs came on Friday for the same reason, and DC Simon Waterhouse on Saturday. Unlike you, they didn’t pull bits off my tree.’

‘I didn’t . . . The tree’s dead,’ said Charlie.

‘Taking its pulse, were you? If dried flowers can be beautiful, why can’t dried trees? I like my garden. I like my dead tree, and its pot. Look at this.’ She led Charlie over to the wall that separated her house from the one next to it. There was something protruding from one of the cracks that looked like a green rose, but with petals that were oddly rubbery, almost cactus-like, pink-edged. ‘Isn’t it lovely?’ said Mary. ‘It’s called a sempervivum. It’s not there by accident or neglect. Someone planted it so that it would grow out of the wall, but you could easily mistake it for a weed. I’m sure you did.’

‘Can I come in for a few minutes?’ Charlie asked, feeling as if she’d lost any potential advantage she might have had. She wished she was in her office, ‘helping’ Counsellor Geoff Vesey to draft his letter and questionnaire—writing them for him, in other words. Vesey was Chair of the Culver Valley Police Authority, an organisation that monitored, among other things, public confidence in the police. Charlie’s confidence in him was zero; the man couldn’t even come up with a list of questions on his own.

‘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.’