‘What pictures, detective? You’ve been asked to describe the room you saw several times. You’ve said you can’t be sure there were any pictures.’

‘Tell us,’ Simon snapped. ‘Were the pictures still on the walls?’

‘No,’ said Milward, after a short pause. ‘The only pictures in the flat were photographs of the happy couple in a range of sizes. In every room, they’d been taken down and leaned against walls and furniture. Leaving only holes. No nails, no hooks.’

‘So, what—he shot her, then knocked her teeth out with . . . what? A hammer?’

‘Why do you say that?’ asked Milward.

‘I’d use a hammer to hang a painting. That’s what he used.’ Simon nodded to himself. ‘How did he cut her lips back like that? A Stanley knife? I saw one at Seed’s workshop.’ He paused for breath. ‘He took down all the pictures, collected the hooks and nails, and hammered them into her lips and gums. Why? What was it about her mouth?’

‘That’s the wrong question,’ said Charlie, standing up. Simon saw that the back of her shirt was dark with sweat. ‘How many pictures were leaning against the walls? How many hooks and nails in Gemma Crowther’s mouth? Did the numbers correspond? ’

Milward looked at Dunning, whose face coloured. ‘It should be in the file,’ he said. She passed it to him and he started to leaf through the pages, his agitation growing more apparent as the silence dragged on.

‘You don’t know how many hooks she used for each picture,’ said Simon.

‘Have you ever hung a painting?’ Charlie asked him. ‘A photograph, anything framed?’

‘Yeah,’ he lied, feeling heat creep up his neck. He’d Blu-tacked a few posters to walls, that was it.

‘You have, I assume?’ Charlie said to Milward.

She nodded. ‘I’m a one-hook woman. I’ve never hung a picture heavy enough to need two.’

‘It’s nothing to do with heavy,’ said Dunning, shooting his skipper a look designed to obliterate. ‘If you use two hooks, the picture’s more likely to stay straight, especially if it’s a big one.’

‘I think there’s a picture missing,’ said Charlie. ‘I think this murder’s about that—that’s why the killer used picture hooks and nails to mutilate Crowther’s face.’

‘Why would anyone want to steal a cheesy photo of—?’ Milward began.

‘Not a photo,’ Charlie cut her off. ‘A painting. It’s called Abberton . It’s by Mary Trelease.’

‘So, this is the table you sat at with Dommie.’

‘Pure coincidence,’ said Charlie with a bland grin. Her heart wasn’t in it. ‘Either that, or this is my table of lust, and I bring all my rides here.’ They’d been dismissed by Milward three quarters of an hour ago. Charlie had hailed the first free cab that had come their way, told it to drop them on Goodge Street.