‘Well, having used the first break-in to measure up and photograph the original painting, Elliot painted a copy, and the night I interrupted him in Stefan’s house, he was attempting to swap them. Of course he was. But the fact we found wood chips on the table by the chisel and hammer should have made us realise that he’d already managed to get the frame from the real Rothko by the time I arrived. So there he was with an original Rothko, an original frame, and a forged painting when I interrupted him and he threw his torch at me. He had a choice to make. Put the frameless forgery on the wall and run off with the real Rothko, or put the real Rothko back up on the wall even though it no longer had its frame on.’

‘I’d have put the forgery up and stolen the real thing,’ Suzie said. ‘Seeing as that’s what I’d broken in to do.’

‘But would you? Elliot had been caught in the middle of a burglary, he knew the police would be along soon enough. And whichever painting he put on the wall, he had to believe we’d work out that it was that particular painting he’d been tampering with.’

‘Which is exactly what happened,’ Becks said.

‘Precisely. So if he’d put his forgery on the wall, it would have been covered in his fingerprints and DNA, or had a hair or two from his glorious head of hair painted into the picture by mistake.’

‘Oh I get it,’ Suzie said, finally understanding. ‘The forgery would have led the police back to Elliot.’

‘So he had to put the real painting back. Which is also why he had to have his bonfire. He had to destroy his fake painting along with the real frame and all of his other practice attempts. But it also explains why he was at such a low ebb when Tanika spoke to him over the bonfire. He knew by that point that he’d killed a complete stranger solely so that he could get his father’s Rothko painting back in his hands, and he’d screwed the whole thing up. He’d carried out the murder, but he didn’t have the painting.’

‘And it was you who’d stopped him!’ Suzie said, delighted.

‘Not a bit of it. We all did it together. Now, we’re coming up to a bend in the river, so if I get the line right, we should be able to let the current take us around.’