‘With the policeman, or whatever he was, of course,’ said Lotti, a sneering note in her voice. ‘The man made Arnold an offer – it really angered him.’

‘What offer?’ asked Tilsner.

‘That he would make sure Arnold got safely back to Britain. And that he would ensure he got a comfortable and lucrative professorship at a university. I think he said a “red brick” university – I didn’t really understand what that meant. But Arnold had to forget about all his research in Dresden. If he didn’t, then his and his wife’s life might be in danger.’

Müller heard Tilsner draw in a sharp breath beside her. But something in Lotti Rolf’s statement didn’t ring true.

‘How would a People’s Policeman, or indeed an agent from the Ministry for State Security, be able to come good on such an offer? Did you stop to wonder that, Lotti?’

The woman was sobbing softly now. ‘There wasn’t time to think about things like that. It all happened so quickly. Arnie flew into a rage. The man was trying to arrest him or something. Anyway, they got in a terrible fight. The man fell over and hit his head at one stage. But then he got up again. They were grappling on some duckboards where the new build was going on. Then the man slipped and we suddenly realised the concrete hadn’t set yet. He was sinking down into it. Arnie grabbed his hand, tried to pull him out, but it was no good. I could tell the man couldn’t breathe, that it was too late. I had to pull Arnie away in the end. He didn’t want to leave him. None of this was his fault.’

‘So you’re saying it was all just a terrible accident?’ asked Müller. There was still something about the woman’s account she didn’t fully believe. When Southwick himself had recovered enough to be questioned, they’d have to see if his account tallied with hers or not.

‘Exactly. We weren’t even sure who this man was. He was very aggressive. But Arnie didn’t mean for him to fall into the concrete. We didn’t even know the concrete wasn’t set. We tried to save him. That was when Arnie injured his leg, on a rusty piece of concrete-reinforcing mesh.’

Müller looked hard at the woman. So much of the story didn’t really square with what they already knew. The pathologist had insisted Concrete Man had suffered a blow to the back of the head that had been inflicted with a blunt weapon. He’d been adamant it wasn’t the result of a fall. Now Lotti was trying to claim the exact opposite.