Tilsner nodded. ‘A certain Dr Arnold Southwick. Lived in Hull, wherever that is. Sounds like it got a pounding in the war, like Dresden. Anyway, I did some checking to see if the border guards had any records of an Arnold Southwick. They did. He arrived at Berlin Schönefeld last autumn to take up a visiting university research post.’

‘In Dresden?’

‘Exactly, at the University of Technology.’ Tilsner started to get up and put on his jacket. ‘I’m just about to go and pay his department a visit. Do you feel up to coming with me?’

*

Müller and Tilsner found themselves being ushered into one of the older buildings at the university, and then a wood-panelled room which looked as though it served as some sort of canteen or refectory where they were asked to wait for Arnold Southwick’s boss, Professor Odenwald.

After ten minutes or so, a dishevelled, grey-haired bearded man arrived, slightly out of breath.

‘Apologies. I’ve just come from a lecture I was giving. I gather you’re from the police, asking after Arnold Southwick.’

Müller nodded, and introduced herself and Tilsner. They both showed the man their Kriminalpolizei IDs. Concentrating on this new lead seemed to have taken her mind off her headache. Either that or the strong painkillers had finally kicked in.

‘Kriminalpolizei? Nothing’s happened to him, has it?’

‘We don’t know at this stage,’ said Müller. ‘We’re just making routine inquiries, and we believe Dr Southwick may be able to help us.’

‘You’re a bit late, I’m afraid,’ said Professor Odenwald. ‘Dr Southwick’s research had come to a . . . a slightly premature end, shall we say. He’s gone back to Britain.’

‘When was this?’ asked Müller.

‘Earlier this month. Or was it late last month? Sorry, my memory’s not what it was.’

‘We’ll need the exact date,’ said Müller. ‘Please check it and phone into the People’s Police offices with it later. So what happened?’

‘I can’t go into any details, I’m afraid. Although the research was under the auspices of the Department of History, it also had government involvement, and was classified.’

‘Classified?’ queried Tilsner.

‘As in secret.’

‘Can you at least tell us the area of research?’ asked Müller.

‘The history of the Second World War.’

‘That’s a rather wide subject,’ said Tilsner. ‘We’re going to need more than that.’

‘I appreciate that. But I’m under oath not to break the secrecy around the project. There are government ministries involved, you see.’

‘Ministries?’ prompted Müller.

‘Well, one ministry in particular. I can give you a contact there, if that’s of any use. They have an office here in Dresden. Here – he left me his card, if you need to copy down the details.’ He offered the business card to Müller.