The traffic’s thickening, more and more SUVs with blacked-out windows are cruising the streets. Which either means we’re heading towards a wannabe-gangsta convention, or we’re getting close to the school. I’ve noticed pick-up time is like a military operation in itself. An old friend had done a tour of duty in Afghanistan, but he said that he’d never been so scared as when he’d started doing the school run. There were women screaming at each other, literally screaming, he’d told me with a haunted look, and then they’d go and stand next to each other at the school gate like nothing had happened.

The road ahead’s clogged up now and I spot a clear side street.

‘Mind if I drop you here? I think it’s going to be quicker for you.’

I find a spot to hover and she reaches for the door handle.

‘Just one more thing. Could you look at the photos of the volunteers and tell me which ones were affected?’

The look on her face says she doesn’t want to, but she eventually nods.

I shift up in my seat and pull the folded photocopy of the volunteers out of my back pocket. She takes it and stares at the images. Then she points out six of them.

‘You’re sure?’

‘You don’t forget stuff like that.’

I’m thinking I should mark them but I don’t have a pen. I take the sheet back and get her to point them out again. I score under each one with my fingernail. She gets out of the car, flips the seat, and reaches for her bike. I can tell she’s hesitating.

‘Go on,’ I tell her.

‘It’s just … the next day I was asked to fill out a patient death form for a man who’d died the week before. I’d filled out a report at the time but it had got lost. So I did it again and took it down to the office where they record all the deaths. I didn’t want it going missing again. Just before I went in I heard one of them talking about the extra deaths from the ICU.’

‘Wouldn’t you expect that from an ICU?’

‘No, it’s about the only department in the hospital which runs under capacity most of the time. I’ve been working here for years, and the most I’d ever heard of being in there at the same time is four. And of those you’d expect roughly half to survive.’

Once she’s gone I glance at the sheet again. DH Biotech’s trial ended with the deaths of some of the volunteers who’d received the experimental treatment. That much seems clear, but what I can’t believe is that DH Biotech have been able to keep it quiet.

I think of the fire investigator’s question.

You got any enemies?