‘No,’ she said. Then, ‘Yes . . .’ Her throat worked but the words seemed lodged there, unable to come out. She suddenly realised that she had no proof. The letter, envelope and all, was gone and nobody but she had seen it. It was like her glimpse of Gerry – for she was perfectly certain now that it had been him in the vehicle, however he had managed to vanish again. And he must have also seen her, for how else would he have known where she was?

‘I can see you’ve had a shock,’ Connor said. ‘Here, sit down.’ He guided her to the chair he’d vacated. ‘Just breathe, and when you’re ready, tell me what the problem is. Or not. It’s up to you. Should I make you some tea? Would you like that?’

His thoughtfulness undid Tilly. She would never have let go otherwise, she later told herself, sniffing furiously and wiping her fingers over her eyes. ‘No tea.’ She shook her head, the words muffled as if answering his query was the most pressing need of the moment. ‘I just – I want . . . I got a letter . . .’ And then it all poured out: the blank sheet, the fire in the incinerator, seeing the message magically appear only to vanish as the blaze consumed it. She could still smell the singed hair on her wrist. ‘Why would he do that? How did he?’ she demanded. ‘There was nothing on the paper until then.’

‘It’s quite a common trick,’ Connor said. ‘Most kids know it. You write the message in lemon juice – or urine,’ he added. ‘Little boys, playing at being spies. It’s the acid in the medium, you see. You apply heat to make it visible. My mates and I, we held the paper over a candle. You don’t actually have to burn it.’

Tilly rubbed damp hands on her shirtfront. ‘But why? If he was going to write to me, why hide it? If I’d crumpled the paper up, I’ve never have seen it. How could he know I wouldn’t just throw it away?’

‘Maybe he thought you knew the trick too? And he might have worried about your mail being intercepted.’

Tilly stared at him, her voice sinking to a whisper. ‘So, it’s true. He’s done something wrong. That’s why the police came. Is that why my daughter is dead . . .?’ This time the tears brimmed and ran over in a stream until she sobbed. ‘I thought, when I saw the message and knew it was from him, that if he had somehow escaped death – then Francie might’ve too . . . That maybe she wasn’t dead? But he wouldn’t keep her from me. Gerry was never cruel.’