‘No.’ I pull the phone out of my pocket. Private number, but it can only be Warner or one of her goons. I reject the call, pocket the phone and hold my palms in front of the heater. Cold like this brings back painful memories of when I was homeless. Some days I worried about losing fingers to frostbite. Seems ironic now, since the room I lost my thumb in was plenty warm.

‘When we worked our last case together,’ Thistle says, ‘you told me you didn’t have a cell phone.’

‘It’s new,’ I say.

‘Sure.’

I change the subject. ‘Did you put a BOLO out on Luxford’s car?’

‘I can’t,’ she says. ‘Not without probable cause.’

‘None of those young women looked like they knew they were on camera. They barely looked conscious. Some might even have been underage. That’s probable cause of three crimes right there.’

The photos themselves are in an evidence bag on the back seat. But I don’t think the forensics team at the field office will find anything useful. We already know who took the pictures, and where.

I wonder why Luxford kept printouts of the photos in his office. Seems risky. I’d like to examine them right now. But with so much flesh on display, Thistle might notice how it affects me. She could misinterpret my interest. Or, worse, interpret it correctly.

‘This is why you don’t open a suspect’s desk without a search warrant,’ Thistle says through gritted teeth. ‘We can’t use any of the photos you found. I can get some agents watching his house, but I can’t get authorisation to search it. Without other evidence, we can’t charge him. Another predator goes free. Nice work, Blake.’

‘He would have gone free either way,’ I say. ‘No one suspected him.’

‘One of those women would have come forward eventually,’ Thistle says. ‘And then so would the others.’

‘How many more women would he have exploited in the meantime?’

Thistle squeezes the steering wheel like she’s trying to crush it. ‘There’s no point solving crimes if you can’t charge the perps, Blake.’

For me there is. I take cases not because the bad guy gets punished, but because I get so wrapped up in the puzzles that my hunger disappears. When I was searching Luxford’s desk, I completely forgot that I was supposed to be sabotaging this case rather than solving it.

I remember the enthusiasm in Luxford’s voice when he talked about the wheel cipher. It was the only time in the conversation when he didn’t seem like a narcissistic asshole. Maybe, like me, he’s a monster except when he’s focused on something that really interests him.

‘We can leave one of the photos out in the open,’ I say. ‘Let them be discovered by Liz. She’d recognise his office.’

‘Now you’re talking about evidence tampering.’