‘Scheisse!’ hissed Tilsner into her ear. He was suddenly pointing up towards the fifteenth floor. Her gaze swung upwards. The light had gone out. While they had been standing here discussing the merits of the case. But they’d kept their voices inaudible, surely? Perhaps whoever it was up there had been keeping a lookout.

They had the same thought at the same time. Müller saw Tilsner draw out his Makarov as she did hers. They slowly advanced into the shell of the building’s lobby.

The lift shaft was simply that, an empty shaft with no mechanism whatsoever. They would be climbing up the stairs, which appeared to be complete. Why had this block been abandoned part-way through construction? It didn’t make sense. Perhaps some vital parts were missing, or some structural defect had been discovered. Or – given the rumours about the Republic’s dire need for hard currency – maybe the money was just running out.

They slowly climbed the stairs, taking extra care as they arrived at each new concrete floor that someone wasn’t about to leap out and attack them.

They tried to keep noise to a minimum. But each false step they made sent clanging echoes through the empty building.

Müller accidentally kicked a metal bolt or screw off the stairs, into the adjoining lift shaft void. They stopped, stock still, as they heard it clatter to the floor far below, like a stone tossed down an empty well.

Finally, trying to control their panting breath, they reached the fifteenth floor.

Müller edged her head round the pillar of the lift shaft, which gave them some protection. She could sense Tilsner doing the same behind her. This storey was an almost complete void both ways, and to the right she immediately saw what had caused the flickering light.

An open fire on the floor, encased by a makeshift structure of grey concrete breeze blocks. It was now just glowing red rather than flickering with yellow flames, as it presumably had been earlier. A human shape covered in what looked like rags or sacks lay to one side of it, with another shrouded human crouched beside.

As quietly as possible, Müller and Tilsner advanced. The two figures didn’t seem to have noticed them yet – either that, or they were beyond caring.

Müller could see, though, that there was no escape for their prey. The staircase she and Tilsner had just ascended was clearly the only way in or out.

‘Freeze, Kriminalpolizei!’ she suddenly shouted. ‘Get up slowly, with your hands above your head. You’re both under arrest.’ There was no evidence of any serious crime, of course, but just sleeping or living rough in the Republic – and not contributing to the socialist workers’ and peasants’ state – was crime enough.

The hunched figure slowly rose to a standing position and raised his or her arms. Only when she spoke did Müller realise it was a female.