I glance at Thistle. She nods slightly—she’s confirmed this with the students.

I let the silence linger for a moment, to see what he fills it with. Maybe he’ll ask how Biggs’s family is doing. Maybe he’ll ask which angles we’re looking at.

He does neither. ‘It’ll just be brewed coffee, I’m afraid,’ he says finally. ‘I have an espresso machine at home. Nineteen bars of pressure.’

So he’s rich, and keen to show it.

‘Those girls you were talking to this morning,’ I say, ‘were they your students?’

‘Which girls?’ He looks honestly perplexed.

‘In the cafeteria. You gave them business cards.’

He laughs. ‘Oh! No, I don’t know them. I was just being friendly.’

‘You try to befriend all the students?’ I ask. ‘Or just the girls?’

He shrugs, not looking embarrassed. This could mean that he’s honest to a fault, not caring or unaware how he comes across to people. But the aftershave, the hair and the outfit don’t fit with that. It’s possible that he’s not embarrassed because hitting on students isn’t so bad compared to other things he’s done.

There’s a knock at the door. Luxford says, ‘Come.’

A young woman walks in, holding a cup of coffee. It’s the same student I saw talking to the blonde beauty in the study nook outside. She has braided hair and a nose ring, and is in a summer dress despite the weather. She wears black leggings underneath, like a dancer. She looks faintly confused, as if Luxford has never instructed her to get coffee before, and she’s just now wondering if it was in the job description.

‘Thanks, Liz,’ Luxford says without getting up. He points at me. ‘Right here.’

Liz hands me the coffee with a glare, apparently deciding that this is all my fault. Then she leaves without a word.

I sip the coffee, watching Luxford. Most people wince when they see me drinking coffee with salt in it. He doesn’t.

‘Do you know what Professor Biggs does on the weekends?’ I ask.

Luxford looks as though he’s never really considered it. Like his boss just ceases to exist between Friday and Monday.

‘Just reads books, I guess,’ he says. ‘About math.’

‘What area of math does he specialise in?’

‘Geometry.’

‘Does he go hiking?’ I ask, still looking for a connection to the body in the woods.

A smug smile. ‘That’s geography.’

‘Oh.’ I let him pretend that I misunderstood. ‘The wheel cipher doesn’t look like geometry.’

‘Geometry was his job; cryptography was his hobby.’

‘Did he have friends who shared this hobby?’ Thistle puts in. ‘A club, maybe?’

‘Not that I know of.’

‘What about shooting?’ I ask. ‘Has he ever talked about hunting buddies, or trips?’