‘Thanks. I’ll talk to you soon.’ Krasic stuffed his phone back into his pocket and closed the cabinet. Time to get out.

Luckily, he didn’t have to fiddle about with his picks, for the door locked automatically when it was closed. He didn’t want to risk the lift, so he headed for the fire stairs at the end of the corridor. Within two minutes he was back outside, ducking into a bar on the other side of the street. He was halfway down a glass of pilsner when he saw her walk into the apartment building. Rado was a comfortable thirty yards or so behind her. Krasic glared through the window at Caroline Jackson’s retreating back. Even though he hadn’t found any reason not to, he still didn’t trust her.

Emil Wolf looked as if he spent most of his life in dusty archives, Tony thought as he sat opposite him in the small café in Prenzlauer Berg. Thin as a whip, his untidy steel grey hair hung over a forehead the colour of parchment. His brown eyes behind oblong glasses were pink-rimmed, his cheeks pale. His mouth was a grim little line, his lips almost invisible until he opened his mouth to speak.

‘I appreciate you giving me some of your time,’ Tony said.

Wolf’s mouth turned down at one corner. ‘Petra can be very persuasive. Did she tell you I used to be married to her sister?’

Tony shook his head. ‘No.’

Wolf shrugged. ‘Petra thinks this still means we’re family. So I have to jump to her orders. So, how can I help you, Dr Hill?’

‘I don’t know how much Petra has told you?’

‘I understand it is a confidential matter relating to a serious crime. And that you think it possible that the perpetrator or someone in his family has suffered abuse at the hands of the psychiatric profession?’

‘That’s right.’

‘I’m presuming because you are talking to me and this is my area of expertise that you think this may have happened at the hands of the Stasi?’

‘It crossed my mind, yes.’

Wolf lit a cigarette and frowned. ‘In the West, people tend to lump the Stasi in with the Soviet Union when it comes to the abuse of psychiatry for political purposes. But really, the dynamic was very different in Germany. The Stasi had huge resources at their disposal, and they used them to build an unparalleled network of informers. It’s been estimated that one in fifty of the population was directly connected to the Stasi in this way.

‘They relied on what they called the “decomposition” of people. Decomposition meant making people feel they had no power to act. They were paralysed as citizens because they were convinced that everything was controlled. One of my colleagues has called this “the relentless application of a quiet coercion leading to compliance.”