‘If you were duped, you weren’t the only one. And we have a feeling that was the intention. The people who set up these flash mobs know exactly what they’re doing. Don’t give yourself a hard time. You weren’t to know.’ I tried to give her a reassuring smile.

Dan was beside me now. He was holding out his phone screen so I could read an email he’d just received. Indra Gudelis had been rushed back into hospital with internal bleeding.

‘OK,’ I said to him. Poor Indra. It’d been one thing after another. ‘Mrs Feldman, we’ll be off now.’

‘OK, dear. Neska, the detectives are leaving,’ Rosa shouted to her daughter. ‘We’ll see you out.’

‘You don’t need to—’

‘Nonsense. I won’t hear of it.’

Dan chuckled behind me as we all filed down the narrow stairs and through the shop to the street.

As soon as we were outside, I turned to Rosa. ‘You go in, back in the warm.’

But she wasn’t listening.

Her attention was fixed on the front of her shop and she was studying a patch of masonry above the door. With the lights on inside, the brickwork seemed lighter than I’d seen previously, and a Star of David was clearly illuminated, etched into the surface with a sharp instrument.

‘I thought anti-Semitism was on the wane,’ said Rosa. ‘Look. They’ve scratched it into the brick.’ She was shaking her head in horror and disbelief, and pointing at the symbol. ‘I hope this doesn’t mean we’re going to have the windows smashed again.’ She put her hand out to steady herself. ‘I don’t think I can cope with much more.’

The star was the height of one brick, so not huge, but it was visible and striking. I certainly hadn’t seen it before. ‘Is this the first time you’ve noticed it?’

‘I think so.’ She looked over her shoulder at me. ‘But I don’t tend to stand out the front and face the entrance. My mind’s usually on the till or I’m carrying a heavy load, so generally I’m rushing in or out. I’m not usually looking that high up.’

‘I haven’t seen it either, but Mum’s not been here for a couple of days.’ Agnieszka had followed us downstairs and overheard. ‘Maybe someone did it then? When I arrived with the kids earlier, I let us in and bundled them upstairs. I didn’t notice it, but we were in a hurry to get inside.’ Concern pulled at the muscles round her eyes. ‘I know you’re Jewish, Mum, but why would someone suddenly decide to scratch a Star of David outside the shop?’