‘I’m not suggesting we run out and arrest him now, you daft bastard. We already know from his prints that he’s been in her apartment. He could spin that any number of ways, but now we have proof that he actually knew her personally. Think it through, though. Locke uses Bolton to intimidate Barclay. He also ends up talking the daughter into bed, and soon after that Barclay sells up, eats a bullet and she goes missing. You honestly think that was just coincidence?’

Anderson just shrugged.

‘Bullshit,’ snapped Porter. He could feel the blood rising to his cheeks, hear the edge creeping into his voice, but he wasn’t going to let Anderson’s indifference infect the case, or his need to solve the puzzle. ‘Whatever he did, he did it for a reason. Who knows what he wanted? Maybe it was to get some kind of leverage over Barclay, maybe it was just an extra little “fuck you” from Locke.’

‘I agree it’s not just coincidence, guv,’ said Styles, ‘but how do we work backwards to figure out what the hell happened? I mean, it’s not as if Bolton is just going to give us a kiss and tell, is it?’

Porter sighed. This was the part of the case still shrouded in a swirl of mist, and the harder he stared at it, the more impenetrable it became. ‘We start by going over the crime scene report again; question any anomalies, anything that looks out of place or doesn’t sound quite right. If we can place him in her flat the day she went missing, we can bring him back in.’

‘We can’t move on him yet,’ protested Anderson. ‘What about Locke? What about doing things right?’

Porter glared at him. ‘If you’d done things right, we wouldn’t have one officer dead and another fighting for her life.’

Anderson flinched as if he’d been slapped, and Porter instantly regretted it.

‘Look, I’m sorry. That was harsh. What I’m trying to say, though, is if we get him for something he did way back then, it takes the pressure off us to pin what happened yesterday on him. Don’t get me wrong,’ he added, ‘I’ll see him done for that as well, but it buys us time to work that case and gets him off the streets.’

‘We can still work the drugs angle as well,’ Styles piped up.

Anderson looked at him and sneered. ‘So, what, then? We never needed Bolton all along, and just jump straight up to Locke? Is that what you’re saying?’

‘No, but think about it. We already have the other guy on tape – Patchett? If Bolton gets taken out of the picture, Locke will need someone else to step in. Whoever that is will work with Patchett, so you turn Patchett just like you turned Carter.’

‘And look how well that worked out,’ mumbled Anderson under his breath.