‘You might have come across the phenomenon of suicide contagion, officers?’ He pauses long enough for the word officers to bed in. ‘Unfortunately this is what I believe was going on here. Natasha was a good friend of another of our students, Jessica Easton. As you might know, Jessica very sadly took her own life a couple of weeks ago. Before that there was another incident, very likely a suicide attempt, by Satnam Mann, who was also a friend of the other two. It starts with one student and spreads to their friends. There was another incident of it, if you remember, at Midland University a good while back now. Four or five suicides that time, I believe. And a plague of copycat suicides in America in 2015, as I recall. Shocking but very difficult to predict or prevent. Studies…’ he tails off, wary of sounding rehearsed.

‘We are aware that copycat suicides can happen, yes,’ says DC Hassan. ‘But…’

Cullen raises a hand to continue. So long as I’m talking, he thinks, they can’t do anything. Can’t arrest me or even ask me questions. He takes a deep breath. ‘It goes without saying that after Jessica…’ he searches in his mind for a delicate expression ‘…left us, the university did all it could to reach out to anyone who knew her, other students, her friends…’ He fleshes out the university’s student welfare policy, its reputation for student satisfaction. Before him, the police officers listen in respectful silence, nod, occasionally glancing at one another. This is going very well, he thinks, very well indeed. ‘So, as I say, you’d be better off speaking to Mark Ratner,’ he says.

The police look blank and say nothing, which is unnerving. Eventually DC W— the woman anyway, he can’t recall her name – cracks a slow and unconvincing smile and says, ‘Your former colleague.’ She checks her notes. ‘Dr Mark Ratner. He’s heading to Thirsk, we believe.’

Cullen blinks, and coughs to buy himself a little time. Have they already been looking into Ratner? He is sure that he hasn’t mentioned Thirsk. They must already know it. Who else have they spoken to? Feeling very rattled indeed, he takes a deep breath. Nothing for it but to talk his way out of this one. ‘If you must know, I think Dr Ratner may have quite a bit to answer for. He is, shall we say, quite one for the young ladies.’ Be careful, he thinks, you don’t want to incriminate yourself here. ‘I don’t know for sure, but it’s possible that he had an eye for Natasha and for Jessica. It’s not unknown for Mark to go off piste, as it were.’

‘Off piste?’ asks the woman.