‘No matter. And the Zhivko bombing? Entirely unrelated?’

‘So far as we can tell.’

Fry wanted to ask Kotsev more. She wanted to ask him lots of things. But there was a hint of distance in his voice that made her hold back.

‘I will be pursuing my own enquiries in Pleven. Meanwhile, if I’m not available, you may speak to my colleague, Inspector Hristo Botev.’

‘Could you spell that for me?’

Kotsev spelled out the name. ‘Hristo Botev. You pronounce the “H” in the throat, almost as if it was a “C”.’

‘It sounds a bit Welsh.’

‘Yes, a bit Welsh. My friend Hristo is very celebrated in Bulgaria. A great hero.’

Fry smiled at his exaggeration. She didn’t imagine that police officers were any more celebrated in Bulgaria than they were in Derbyshire. For most people, they were a necessary evil, at best.

Cooper came into the office, and saw at once that something was disturbing Fry.

‘What’s up?’ he said.

‘That was Georgi Kotsev. He’s going back to Bulgaria this morning.’

‘Well, his interest in the case is over, I suppose.’

‘Not really. We still don’t know where Luanne Mullen is. Or should I say Zlatka?’

‘If she’s not dead, she’ll be back out of the country by now. Don’t you think so?’

‘Georgi does.’

‘Well, then. Sergeant Kotsev will be more use back in Bulgaria, if she’s ever going to be found. I think they did the right thing recalling him.’

‘Yes, you’re right.’

Cooper hesitated, wondering whether he should voice what was on his mind. The picture he had in his head seemed so unlikely that he was sure he must have imagined it. It was surely a false memory, an impression mixed up with something he’d seen in Derwent Gardens. Something, or someone.

‘It’s a pity, though,’ he said tentatively. ‘There was something I wanted to ask Georgi.’

‘Anything important?’

‘It was something I remembered from the incident at Masson Mill. Just before I ended up in the water.’

‘Before you decided to take a swim, Ben?’

‘Yes. Well, it was a very brief impression I had, but I thought someone else was there by the river that night.’

‘Obviously there was – the person who pushed you in.’

‘No, that wasn’t what I meant. There was someone else, further away. I had the impression – well, I wanted to ask Georgi Kotsev whether he’d seen a woman.’

‘A woman?’

Reluctantly, Cooper tried to describe his half-memory. It was no more than a shadow flickering in the darkness, perhaps the rustle of a long skirt on concrete. He might have been describing a dream. Or he might have confused it with the earlier glimpse of a woman who looked like a fortune teller, her blue scarf flashing briefly in the lights in Derwent Gardens.