‘Not always, but Natasha seemed the anxious type, you know, the sort who might have to take something to steady herself, get through the day.’ He is thinking on his feet now. ‘You’d be better off talking to my colleague…’ he corrects himself, ‘…former colleague, Mark Ratner. He had more to do with her than I did. My role as Dean means that my teaching load is lighter and I generally focus on my area of expertise.’

‘Which is?’ asks DC Worsley.

Why are they asking me this, he thinks, they must know already, surely? All it takes is a quick google.

‘The application of mathematics in the life sciences. Statistics, probability, modelling, that kind of thing.’ He leans back in his office chair, feeling suddenly rather more at home.

Looking up from his notebook DC Hassan says, ‘Can you tell us about the last time you saw her?’

For an instant Cullen’s mind toggles back to Zoe. He blinks away the thought and takes a deep breath, staring at the ceiling in a simulacrum of remembering, then looking first at Hassan and then at Worsley, he says, ‘I’m not sure when that would have been exactly. Oh, wait a moment, yes. We were obliged to hold a fitness to study meeting with her.’

‘We?’ asks DC Hassan.

‘Yes, the head of student welfare, Dr Lea Keane, and myself. When a student is struggling academically, we request a meeting to talk about how to improve things. Unfortunately Natasha had proved herself to be unsuited to the rigours of Avon. As I remember, we suggested a transfer to another, less academically exacting, course at another university. She wasn’t very happy about it. I hope we didn’t inadvertently set the stage for what was to come, but I’m afraid that, these days, quite a few students come to us who really aren’t well suited for the academic life.’

‘And Natasha was one of those?’ asks DC Worsley.

‘Yes,’ Cullen says, decisively, then when neither of the pair responds, he goes on, ‘I can show you her academic record if you like. Very poor.’

Another exchange of looks between Hassan and Worsley. What are they plotting? The thought suddenly arises that they may have spoken with Nevis Smith. But they wouldn’t be minded to believe anything she said, would they? Hassan and Worsley are probably not the sharpest tools in the box but even they would see Nevis’s claims for what they were – the delusions of a girl with a crush on her teacher. His mind steps back to that lunch at Luigi’s. He blinks to rid himself of the memory. Focus, that’s what’s required here. Outwit the enemy.