‘Well, I’m all for deluded optimism,’ said Lisa. ‘For as long as I live, I’m going to believe you lot are just about to catch him.’

Sellers felt winded. What she’d just told him, without realising it, was that she expected them never to catch Billy. Corresponding with Sellers’ own fears as it did, that wasn’t an easy thing to hear.

‘It’s the only way I can live. If this were a movie, I’d say, “When you catch him, don’t arrest him – bring him to me. Let me deal with him.” God, the fantasies I have about what I’d do to him. And then I wonder if I’ve allowed a monster to turn me into a monster,’ Lisa added tearfully.

‘You’re no monster. Every single relative of a murder victim has those same revenge fantasies. The police have them too.’

She sniffed, then giggled. ‘Hey, do you fancy a cocktail? I’m no mixologist, but how hard can it be? It’s just shaking up some booze and sticking it all in a glass at the end of the day, isn’t it?’

Sellers, who’d had too much to drink the night before, couldn’t think of anything he wanted less. ‘Tell you what,’ he said. ‘You make us cocktails – though not too much of the hard stuff in mine, if that’s okay. While you’re doing that, I’ll do my walkaround of the flat.’

‘Deal,’ said Lisa. ‘Josh had a silly song he used to sing whenever he made a cocktail. He called it his magic ingredient. If he didn’t sing the song, the cocktail wouldn’t taste right.’

Please don’t sing.

She waited, at least, until he was out of the kitchen and the door was closed. Sellers listened from the hall. It sounded like a skipping song schoolkids might sing: ‘Happy llama, sad llama, mentally disturbed llama, super llama, drama llama, big fat mama llama. Llama llama llama! Who is this big llama causing all the drama? It’s me, bitch!’

Sellers raised his eyebrows at the abrupt ending. Lisa started to sing the same words again. Josh’s cocktails must have been amazing, thought Sellers, if his guests were willing to put up with the llama song on an endless loop. Or perhaps the aim was to instill in them a desire to get drunk as quickly as they could.

Josh’s bedroom and lounge looked exactly the same: nothing had changed, moved or been added. There was only so much looking at two small rooms one could do. Standing around hoping for something to magically appear was pointless.

Doesn’t make this a pointless exercise. You’ve already learned something new: Josh’s llama song. It might be ridiculous, but you didn’t know it before. No one working on Billy did. Which means something else, something useful, might also be here for the taking.

Sellers opened the drawer in the TV stand, looked under the chair and the two sofas. Nothing.