Something in Isobel’s Carlisle’s manner – an underlying aggression – made Thomas want to run. He didn’t envy Bellerose having to conduct an investigation with the likes of Isobel Carlisle hovering about.

‘This is Thomas Charles,’ Bellerose said. ‘He is helping me.’

‘If you’d do your jobs this would be resolved by now,’ Isobel said.

‘Where is Mr Blackwell?’ Bellerose asked.

‘Upstairs, last door on the right. Now, if you’ll excuse me.’

Thomas followed Bellerose up the stairs and along the dark hallway. The thick carpet muffled their footsteps. They stopped before the last door on the right.

‘Perkins, you stand on the inside of the door in case he makes a run for it. Simmons, you stay out here.’ Bellerose knocked.

‘Mr Blackwell? It’s Chief Inspector Bellerose. Police.’ Bellerose opened the door. He and Thomas stepped inside.

The stench of the stale cigarette smoke assaulted Thomas as he and Bellerose stepped into the room. The curtains had been left open. No lamps were lit, and the gloom seeped into every corner.

Michael Blackwell’s imposter sat on a chintz chair tucked into the corner. An ashtray filled with dirty cigarettes sat next to him. A tray with a half-full bottle of brandy sat on the table within reach. Michael Blackwell didn’t move when the men walked in. His skin was pale and shiny with perspiration, his shirt damp at the armpits and dingy around the collar. God only knew how long he had been sitting there. Thomas wondered if Blackwell’s impostor was on a mission to drink himself to death.

Michael Blackwell looked at Thomas with bleary eyes.

‘Mr Blackwell, my name is Thomas Charles –’

‘You know, don’t you? You found out. I killed them.’ He ran his hand over his face and took a sip of brandy. ‘I’m glad it’s over. Relieved.’

Bellerose moved close to Blackwell, as if he wanted to speak to him. Thomas waved him back.

‘When’s the last time you had something to eat?’ Thomas asked.

Blackwell looked at him with bleary eyes. ‘Can’t remember.’

He opened the door that led to the hallway and said to Constable Simmons, ‘Find this man something to eat, will you please? A pot of tea, some bread and butter.’

He stepped back into the room, walked across to the window, and opened it so the fresh rain-drenched air could circulate. Thomas resisted the urge to stick his head outside and take in great gasps of the sweet clean air. Instead, he went to the wardrobe and pulled out a clean shirt.

‘Here.’ He thrust the shirt at Michael Blackwell. ‘Go and have a wash. You can use the bathrooms up here. Wash your face and change your shirt. Get yourself sorted. When you are finished, you can explain who you really are and what you’ve been up to.’

‘I think he might need a doctor,’ Bellerose said. ‘He seems like he is about to crack.’

‘He does. He is. We’ll get him seen to. After I speak to him.’

Michael Blackwell came back into the room.

‘Have a seat. Get comfortable. Then you can tell me who you really are and why you’ve impersonated Michael Blackwell.’ The impostor sat back down in the chintz chair, while Thomas pulled a chair from the writing table next to him and sat down in it. He leaned back and crossed his legs, settling in to wait. This man would talk; Thomas was sure of it.

‘I’ll tell you everything. Just don’t send me back. They’ll kill me if I go back.’

A constable came back with a tray laden with a mug of tea and several slices of bread and butter. The man ate hungrily. After he gulped down the tea, Blackwell poured straight brandy into his teacup and drank it. He sat for a moment, staring at nothing in particular.

‘I’m so tired of all the lies. These people have been so kind to me. I’m glad this is over. I don’t mind what happens to me, just don’t send me back.’

Thomas waited.

‘My real name is Dieter Reinsinger. Michael Blackwell was married to my sister, Leni. The Gestapo took them. They’re dead. I’m sure of it. It’s all my fault. That part of my story is true.’

‘Perhaps you could start from the beginning,’ Chief Inspector Bellerose said.

Dieter Reinsinger nodded. ‘I was an accountant in Berlin. I had a good job, made a good wage, and was able to provide for my sister, Leni. I felt responsible for Leni’s welfare. Our parents died, you see, when we were in our early twenties. We only had each other and we were very close. Leni was a beautiful girl with a romantic streak and wild ideas. She kept house, dabbled a bit in the arts. Leni was a romantic, a dreamer.

‘She met Michael Blackwell in 1928 at a friend’s dinner party. She kept their relationship a secret. They married. We all lived together in my apartment. I hoped my sister would settle down, give up her wild schemes.’

Bellerose stepped close to Dieter, as if he wanted to say something. Thomas shook his head. Bellerose stepped away. They waited.

‘I hated him,’ Dieter said. ‘He was everything I wasn’t. He was brave, where I was a coward. He spoke out about the way things are in Germany now. I was too afraid to do so.

‘He took my sister away from me. He put her in danger …’ Dieter’s voice drifted off. Thomas waited.

‘I tried to ignore the way Germany changed, as if that would stave off the inevitable. In September 1935 when the Nuremberg Laws were passed, Michael was outraged and he didn’t care who knew his feelings.’ He looked at Thomas with such sadness, Thomas almost reached out to him. ‘I don’t know why the Jews are so reviled. I don’t understand it. Businesses were seized. Jews were no longer citizens of Germany, but subjects. The laws forbade Jews from practising medicine, teaching at universities, or holding civil service jobs. It’s unbelievable that your newspapers don’t report on this. And the people in Germany just go along with it. No wonder Michael was so agitated.’

He reached for a pack of cigarettes with a shaking hand. Thomas took the pack from him, put a cigarette in his mouth, lit it, and handed the lit cigarette to Dieter. Dieter took it, nodding his thanks. ‘Our next-door neighbours, the Neibaums were the first to suffer. They were quiet people. He was an antique bookseller, who lived a quiet life with his wife. One of their letters was accidentally left in the neighbourhood gossip’s post box. She accidentally opened it, and soon everyone on our street knew that Mr Neibaum had inherited a substantial amount of money from a long-lost uncle. He wanted to start an orphanage with the money.

‘I was just coming home from work when the men came. They hit him with a stick and told him that if he didn’t leave the country, they would take him and his wife to a camp.’ Dieter gave a hollow laugh. ‘Mr Neibaum lay in his courtyard, his teeth knocked out, his leg broken, his body beaten and battered. Of course, he agreed to leave. Not that he had a choice. But there was a price to be paid for his freedom.’

‘What price?’ Thomas asked.

‘His inheritance. The only way he could get an exit visa to leave the country was to pay the tax – ninety per cent of his inheritance.’ Dieter wiped his eyes.

‘What does this have to do with Michael Blackwell?’ Thomas bit back his impatience.

Dieter flashed an irritated look at Thomas. ‘Everything. Michael was an educated man, with a deep knowledge of politics, economics, and history. He and Leni were up to something. I knew it. I’m sure my neighbours knew it. When they went out, I searched Michael’s wardrobe and found a box of brochures, innocuous-looking at first glance, entitled Learn About Beautiful Germany. I reckoned that Michael – who freelanced as a writer – had written the brochures to sell for the upcoming Olympics.

‘Curious about Michael’s writing, I opened the brochure. What I saw inside was not information about beautiful Germany. Instead, he had written a scathing indictment of life under the Nazi regime, along with a map of the locations of all the camps. By this time, the Gestapo was watching us. It was just a matter of time before they raided our house. When they found the brochures, they would take us all away.

‘I hated him. He put my sister – and me – in danger. I had to do something. You see that, don’t you? I couldn’t just sit by and do nothing.

‘I came home from work one day, just in time to see Leni and Michael loaded into the back of a black Mercedes. Michael struggled. Actually punched one of those Gestapo thugs in the nose. They retaliated by knocking Leni down. I watched from a neighbour’s porch, too cowardly to do anything. They weren’t supposed to take Leni.’ Dieter closed his eyes and bowed his head. The grief emanated from his very essence. ‘They shoved them in the back of the car. As the car drove away, I knew I would never see my sister again. I thought about killing myself. I should have.

‘I went into our flat and took the money we kept hidden under a floorboard in the kitchen. Michael Blackwell’s passport was hidden there as well. As I held my brother-in-law’s passport in my hand, I realised that we resembled each other. Our colouring was the same, and the photo was old enough to account for any minor differences in the way we look. I took the passport and the money and went to the British Embassy in Berlin. I told them I was Michael Blackwell, and that the Gestapo had taken my wife and her brother. They managed to get me out of the country.’

‘And you came knocking on Benton’s door posing as an imposter?’ Thomas said. ‘Taking a bit of a risk, weren’t you? What if they asked about long-lost Aunt So-and-So?’

‘I had nowhere else to go. What would you have me do? I knew enough about Isobel and Benton to get by. Michael spoke often of his perfect English childhood. He used to regale Leni and me with stories of his antics with Benton and Isobel when they were young. Swimming, tennis, horseback riding, skiing in Switzerland in the winter. I knew about Michael’s father’s house in Bournemouth and the ghost stories that he used to tell Isobel when they were children.’

Dieter shook his head. ‘Michael Blackwell was a raconteur. When Michael told us his stories, Leni and I clung to his words, captivated by his life here. Benton and Isobel hadn’t seen Michael since he was a boy. Benton – for all his drinking, and the shoddy way he treated his wife – welcomed me with open arms. Of course, Isobel followed suit.’

Dieter took a slice of the buttered bread. While he ate, Thomas moved over to the window. Thomas believed the man’s story. This man didn’t have the courage to steal documents from Benton and pass them off to Marlena X, nor did he have anything to do with Benton Carlisle’s murder. He was too fragile to have killed Benton. Why would he harm the man who had taken him in and given him shelter?

Bellerose stood in the corner of the room. He leaned against the wall. His eyes were hard, his lips pursed.

‘Did you steal documents from Benton?’ Thomas watched Dieter’s face, looking for any sign of duplicity.

Dieter stopped chewing. He met Thomas’s gaze directly. ‘No. Of course not.’

‘Why did you say you killed them?’ Thomas asked.

Dieter looked at him, startled at first, then embarrassed.

‘You said it was all your fault. What did you mean?’ The compassion slipped away from Thomas’s face. In that brief instant he saw Dieter’s cowardice. He knew what Dieter had done. Now he wanted the man who sat across from him to give words to his betrayal.

‘I called the Gestapo,’ Dieter whispered.

‘You called the Gestapo on your own brother-in-law? Now I know why you stay drunk. I’d do the same, if I were in your position.’

‘Don’t judge me, sir,’ Dieter said. ‘I was trying to look after my sister, and my efforts got her killed. I have to live with that.’

‘We should send you back,’ Thomas said. There was a cold edge to his voice. ‘Let you suffer like your sister did, like Michael Blackwell did.’

‘You gave me your word,’ Dieter Reinsinger said.

‘I know,’ Thomas said. ‘I’m now wishing I hadn’t.’

Bellerose spoke. ‘Is that all, Mr Charles? I’ll take it from here, with your permission. Mr Reinsinger needs medical attention.’

Thomas turned his back on them and stared out the window. Outside, the rain had stopped. A woman stepped into an alleyway to put her umbrella down. She shook it before she rolled it up and stuffed it in the shopping bag she carried. Puddles had formed in the street, like small sun-dappled lakes. Two children wearing rubber boots stomped in one, only to be admonished by the nanny who trailed after them.

Another woman loitered beneath a tree at the entrance to the square. She didn’t carry an umbrella. Instead she wore a large hat that all but covered her face. Thomas recognised her right away. His heartbeat quickened. Marlena X. Below him, Mrs Carlisle stepped out the front door of the Carlisle house and onto the pavement, hatless, without her handbag or a coat. She walked towards Marlena X, back straight, her steps sure.

‘No,’ Thomas called out through the open window.

Marlena X looked up at Thomas. She smiled at him, knowing that he couldn’t reach Mrs Carlisle in time to save her, knowing that Thomas would give chase, and she would lead him right into her trap. Helpless, Thomas watched as Marlena X turned and hurried away, with Mrs Carlisle in hot pursuit.