‘But he couldn’t prove we did it.’

‘You don’t get it, do you? I am law enforcement,’ Thistle says. ‘I don’t get to make up my own rules, and nor do you.’

She’s crossed that line before—admittedly not as far as I have. Maybe something happened between now and then that has made her stricter.

Maybe that something was me.

‘You didn’t bring me in to catch a sleazy TA,’ I say. ‘I’m here to find a missing math professor. Now we have some leverage over Luxford. We can use it to find out what he knows, even if we can’t charge him.’

‘For all we know, Luxford has nothing to do with Biggs’s disappearance.’

‘You think it’s a coincidence that there was a sexual predator in his department?’

‘It’s college. There’s probably a sexual predator in every department,’ Thistle says. ‘If you’re so sure Luxford is involved, we should be going to his house, not driving to Biggs’s place.’

We should—except I don’t want Thistle with me when I find Luxford.

‘He’ll turn up,’ I say. ‘But Biggs is my priority. I want to meet his wife and daughter.’

‘Fine. But so help me, if you touch a single thing in their apartment without asking for permission, I’ll arrest you.’

‘That might not inspire much confidence with Biggs’s family.’

‘I mean it, Blake. I’m this close to kicking your ass off the case. To hell with the director.’

‘Okay, okay.’ I turn to the window, and watch the crummy parts of Houston disappear as we drive towards Southampton. The houses get bigger, the lawns greener, the cars shinier. Most of them even have four wheels, which is a nice change from where I live. Apartment buildings on the horizon.

‘I want to know if Biggs’s prints are on any of those photos,’ I say.

‘You think he and Luxford might have worked together?’

‘I’d like to rule it out.’

Thistle nods. ‘So would I. But Biggs doesn’t have a criminal record, so we don’t have his prints on file. No DNA, either.’

‘Can’t we get both those things from his house? Prints off his keyboard, DNA off his toothbrush?’

‘Toothbrush DNA is hit and miss. Hairbrush, too, unless you get a follicle. It would be more reliable to get a cheek swab from his wife and his daughter, compare the two samples and extrapolate Biggs’s genome from that. But we don’t have much of a budget for this, and there’s a huge backlog at the field office. It’ll take us a day or two to get someone to analyse the prints, and DNA will take even longer. Remember, this isn’t a homicide investigation.’

‘Yet,’ I say.

CHAPTER 7

CHAPTER 7

Three people fall out of a boat.

Only two get their hair wet. Why?