Mary’s surprise was unmistakeable. ‘Yes. Well . . .’ She frowned. ‘I don’t exactly know her. I’ve met her twice. I’m hoping to persuade her to sit for me. Why?’

‘How did you meet her?’

‘Why’s Ruth of interest to the police?’

‘If you could answer my—’

‘This is someone who’s been inside my home.’ Mary’s voice was shrill. Frightened, thought Charlie. ‘Why are you asking about her? Has she got some connection to this Aidan Seed person?’

‘How about we do a swap?’ Charlie suggested. ‘You show me some of your work, I answer your question. I am interested, although I know sod-all about art, except that all the best stuff seems to be by dead people.’

Mary’s face went rigid. She stared at Charlie. ‘Are you playing games with me?’

‘No.’ Of all the pissing stupid things to say. All over her body, Charlie’s skin felt cold. ‘I meant, you know, Picasso, Rembrandt . . . I meant that nowadays art seems to mean slices of dead cow and balls of elephant dung.’

‘I’m not dead,’ said Mary very carefully, as if she wanted Charlie to pay attention.

Charlie thought that people who believed in ghosts deserved to have their brains confiscated indefinitely. She couldn’t understand why it should freak her out so much to be standing in the kitchen of a shabby ex-council house listening to a straight-faced woman insist that she wasn’t dead.

‘I’m alive and my work is excellent,’ said Mary less vociferously. ‘Sorry to jump down your throat, but it’s depressing to hear what Joe Public thinks: that anyone with talent is famous already, basically. And dead, of course—all geniuses are dead. If they died young and tragically and in poverty, then all the better. ’

Charlie exhaled slowly. Simon hadn’t told Mary what Aidan Seed had said about her. Neither, he’d told Charlie, had Gibbs. What did it mean? What did any of it mean?

‘Do you think you need to suffer—I mean suffer deeply—in order to be a true artist?’ Mary asked, screwing up her eyes, pushing her wild hair behind her ears with both hands. Was it scorn in her voice, or something else?

‘I wouldn’t say the one follows from the other,’ said Charlie. ‘You could suffer the torments of the damned and still not be able to draw or paint for toffee.’

Mary seemed to like that answer. ‘True,’ she said. ‘Nothing great is so easily reducible. I asked DC Waterhouse the same question. He said he didn’t know.’

Another thing Simon hadn’t mentioned. He’d certainly have had an opinion, thought Charlie. Clearly he hadn’t wanted to share it with this peculiar woman.