Sometimes he heard them, the local Viennese Serbs, as they spoke dismissively of Muslims and Croats, just as others uttered calumnies about Jews or Blacks, creating a hierarchy of misery and pain, a tacitly accepted list of those whose destiny it was to suffer and die. What the ignorant did not understand was that the executioners were always the same, and only the uniforms changed. In that sense, the identities of the victims – their race, their color, their religion – were irrelevant: reduced to bone, we are all identical. When it came to mass murder, any prey would do, and those who would kill one would kill all. They who remembered this, they who had helped to excavate from pits the bones of men, women, and children, could only keep watch in the hope of warning the world when the next batch of executioners made themselves known.

Two men, one older, one younger, passed across his field of vision, breaking his train of thought. They took a shortcut over the grass, and in doing so crushed the edge of a flowerbed beneath their shoes.

‘Hey!’ said Nahid, in German. ‘Watch where you’re treading.’

‘Fuck you,’ said the older man, not even bothering to look back.

‘Fuck me?’ said Nahid. ‘Fuck me? No, fuck you. Fuck you!’ He took out his cell phone to film the two men trampling the blooms. You could say what you wanted about the Austrians, but they placed a premium on law and order, and they really liked their flowers. Nahid planned to show the footage to the park authorities, and perhaps post it on the Internet as an example to others.

Nahid found himself lapsing into Arabic, as he often did when fury got the better of him, the Arab tongue being even more creative than German or Serbo-Croat when it came to insults. ‘Kess ikhtak!’ he shouted, and then, just in case the object of his ire didn’t have a sister, he added ‘Kess ommak!’, on the basis that he certainly did have a mother, and so could go fuck her instead. If she was living, all the better. If she was dead, he could dig up her corpse and fuck that.

The older man stopped, and now he did turn back, even as the younger one with him tried to steer him away.

‘Ya kalb!’ he screamed at Nahid. ‘You immigrant dog! You fucking Turk!’

The expression on Nahid’s face changed, and he lowered his phone.

‘I know you,’ he said, so softly that he might almost have thought that it had gone unheard were it not for the way the younger man’s head tilted slightly in response. ‘I know you. From the film …’