‘I see,’ said the Snowman, wanting her to see he was sickened by what he’d heard. His sickened look was similar to his despicable traitor look; one suggested disgust provoked by stupidity and the other disgust inspired by treachery, but that was the only difference. ‘So we’re in the realm of rubbing lamps and waiting for genies to appear, are we?’

‘Aidan Seed painted a picture called The Murder of Mary Trelease. Martha Wyers destroyed it along with all his others, so obviously we don’t know what it depicted, but Ruth Bussey thinks there was something significant in it, and I’m inclined to agree with her. There must have been something, so that when Wyers found out from Kerry Gatti that Aidan’s stepfather was banged up for killing a Mary Trelease, she thought she knew that he hadn’t. Seed isn’t yet strong enough to answer all our questions, and I’m not sure when he will be, but . . .’

Charlie paused; looked at Simon. He nodded. She’d got this far—might as well let the Snowman hear the rest.

‘After Trelease destroyed all Aidan’s pictures from the TiqTaq exhibition, she painted her own versions of them.’

‘We’ve found seventeen of these in her house,’ Kombothekra chipped in. ‘Only one’s missing. You can guess which.’

‘I’m almost certain that once Mary—sorry, once Martha realised that one of the pictures she’d destroyed was possible proof that Aidan had committed a murder, she immediately painted a version of that picture herself, from memory. Why wouldn’t she? She painted copies of the other seventeen pictures from his TiqTaq show.’ Charlie paused for breath before saying, ‘Ruth Bussey agrees with me, sir.’

‘Well, then.’ Proust’s voice was granite. ‘What more could I hope for in the way of verification?’

‘Sir, if we can find that picture, maybe show it to Len Smith . . . I mean, I know a painting doesn’t exactly prove anything, but we could maybe use it as leverage, to get him to talk . . .’

‘Remember when you and I sat in a noisy café in town, sergeant, and you told me you weren’t good enough for CID? I’m inclined to agree. I wasn’t then, but I am now. You’re talking about a painting that might not exist. Have you asked Martha Wyers’ parents about it?’

‘They couldn’t help us, sir,’ said Kombothekra.