‘Six months or so ago,’ said the woman. ‘Right at the beginning of construction.’ So the mortar shouldn’t have looked as fresh and new as it did, thought Müller. ‘They didn’t do a very good job, mind you, officer.’

Müller’s antennae began to quiver. ‘Why do you say that?’

‘Well, it’s already loose. We’ve asked the building team to fix it several times – they always seem to be too busy.’

‘Where can I find the building team?’

The woman checked her watch. ‘At this time, you won’t. Their site hut’s up at the top of the hill, where the Leutewitzer Ring bends round, but this will be their lunch—’

Müller didn’t wait for the woman to finish her sentence. She ran back outside and then motioned Tilsner and Bahlow towards the Stasi officer’s car.

‘Are you going to tell us what’s going on?’ asked Tilsner.

‘We need to drive to the top of the hill, as quickly as possible.’

*

The site hut looked shut. Müller rapped on the door.

It opened slowly, and a corpulent man who was almost a Doppelgänger for Bodo Achterberg appeared in front of them.

‘What?’ he asked sullenly.

Müller again showed her ID, but the man looked less than impressed at being disturbed – police or not.

‘Has the building team done any work recently at the pub-restaurant down the hill?’ she asked.

The man looked at her as though she was mad. ‘How the hell would I know? I’m just the security guard.’

Müller glared at him. ‘Are there log books of the work that’s been undertaken? Repair requests? That sort of thing?’

‘You’re asking the wrong man. They’re all on their breaks. You need to come back later.’

Tilsner suddenly lurched forward and grabbed the man, pinning him by the throat against the door frame. ‘Do you want to be arrested and spend the night in a police cell?’

The man coughed as he fought to breathe, then rasped out a ‘no’. He seemed to be frantically looking over Tilsner’s shoulder. Then he saw something and slumped in relief.

‘There, behind you in that mustard-coloured Trabi.’ Müller turned and saw a man enjoying a quiet smoke in his car, oblivious to what was going on a few metres away. ‘That’s Wilhelm, the site foreman. He sometimes sits in his car to have his lunch – thank God he’s still here. He’ll be able to tell you all you need to know.’

*

Once the man called Wilhelm had been brought over to the hut, Tilsner finally released the other man, who sank heavily into the office’s only chair, rubbing his throat.

Müller asked the same questions of Wilhelm that she had of his colleague a few seconds earlier.