‘The thing is,’ Savannah went on. ‘I wasn’t really getting anywhere. To be honest with you, I’ve never been convinced the people in the camps know details about trafficking. There are lots of rumours, sure. But if you think about it, by the time someone’s been trafficked, and realised what they’ve got themselves into, they’re miles away from the camp. And they never come back.’

‘Yes,’ said Casey. ‘But I suppose they all know enough to be scared.’

She thought of a group of teenage girls, in their brightly coloured dresses, giggling by one of the wells in the camps. They wore the thick eye make-up that all the Rohingya girls wore, even the small children.

A man had smiled back at them; just a smile at first.

But there was a sudden explosion of fury from a mother, as she charged down the slope. Get away! You get away from my daughter. We’ll get you . . . We’ll . . .

He would be back, though, that man, the next day, and the next. More friendly, and less shocking, every single time.

‘Sure,’ said Savannah. ‘The refugees know to be scared all right. But the who, and the how, I don’t think they know that, really. It’s in the interests of the traffickers that no one knows exactly how they operate. Stop it, you bugger.’ A slam. ‘Sorry. Cockroach.’

But the refugees had guessed some of the routines. Casey had spoken to a mahji, one of the refugees’ leaders, in the Balukhali camp. So casually, he had pulled out his phone, and scrolled through the photographs. This is what we did to a kidnapper, the fixer had translated coolly. Look. See.

The man – she thought it was a man – was mangled far beyond survival, his face unrecognisable. A pearly gleam of bone showed through, here and there.

We sorted him. A smile.

‘And there’s the shame too, for the families.’ Savannah was still talking. ‘Even if the mothers know what has happened to their daughters, and where they are, it would bring such shame on the whole family to acknowledge that their girls have been taken that they don’t want to talk about it. They hide it, usually.’

‘So what have you heard now?’

Savannah’s voice changed. ‘One of the mothers came to me this afternoon, just as I was walking out of the camp. She was waiting on the path, right away from her section. I’d spoken to a few of the women that I work with regularly about what you wanted to know. Asked them to put out the message.’

The charities had set up systems to communicate with the camp residents, usually about health advice. Trained refugees went from tent to tent, recommending vaccinations and sharing other bits and pieces of advice. It was a crucial system, in a semi-literate society. Private, too.