There’s a study, with a desktop computer. Two monitors. The whole set-up looks pretty new—not many cables to the back. Power only. Must do everything through wi-fi. A string of thirteen seemingly random letters that could be a password is written on a post-it note.

‘Ground floor clear,’ Thistle hisses. Then she heads for the stairs.

I follow her up. The staircase slows us down, and it’s narrow. No room to dodge. If anyone was planning an ambush, this would be the place.

We reach the top unharmed. There are two bedrooms and one bathroom. No renovations up here. The bathroom has old-fashioned curved fixtures, and a little mould in the corners of the ceiling. Not uncommon in Houston, where the winters can be as brutal as the summers. People shut their doors and windows, closing off the outside world. Bad things grow in the resulting stillness.

One bedroom is being used for storage. Boxes of summer clothes, crates of sports gear, a stepladder. The sort of thing Luxford would probably keep in his basement, if he had one.

Thistle checks the wardrobe. ‘Clear,’ she says. I wonder why he leaves all this junk on the floor when his wardrobe is empty. No clothes, even.

The other bedroom has a large bed with a thick mattress. Winter clothes hang on hooks in the closet. Neat rows of non-fiction line the shelves.

‘Upstairs clear,’ Thistle says. Then, when there’s no response, she yells, ‘Upstairs all clear!’

Albrecht’s voice seems to come from a long way away. ‘Roger that.’

I start flicking through Luxford’s books, looking for notes tucked between the pages. Nothing. A modern trade-off. These days, if you have a suspect’s phone, you know basically everything about him. But without it, you know nothing.

In his bedside table, I find a Taser.

I go through the pockets of his clothes. The Blu-rays on his shelves. I can hear an air-conditioner running somewhere. I walk around until I find it, a large unit with pipes disappearing into the ceiling and the walls. I open the unit and check the inside. But there’s no journal, no gun, no secret hard drive.

In the ceiling of the closet of the storage room there’s a trapdoor. I use the stepladder to push it up, and then push my head through.

It’s a fairly roomy crawlspace. Nothing here, not even insulation. No indication that Luxford has ever been up here.

When I climb back down, Thistle is waiting. ‘Anything?’ I shake my head. ‘Maybe Vasquez can get something off his computer. But he has a lot of cryptography books, so maybe not.’

‘I’m starting to wonder if he was telling the truth about Biggs having cryptography as a hobby,’ Thistle says. ‘I think it was his.’

‘Why lie about that?’

‘I don’t know.’