Rob leaned out of the apartment. The city was thrumming. Bread-sellers were parading the busy streets, carrying on their head big trays of rolls and sweet pastries, and pretzels with sesame. Mopeds rode the pavements, avoiding dark-skinned schoolgirls with satchels.

Rob heard the bang again. He scanned the scene. A man was cutting baklava with a pizzaslicer in a shop across the way. And once more: Bang!

Then Rob saw a motorbike: an old, black, oily British Triumph. Backfiring. The owner was off the bike, and was now angrily hitting the machine with his left shoe. Rob was about to duck back inside when he saw something else.

The police. There were three policemen climbing out of two cars along the street. Two of them were in sweat-stained uniforms, the third in a dapper blue suit and a pale pink tie. The policemen walked to the front door of Christine’s block, sixty feet below and paused. Then they pressed a button.

The bell in Christine’s flat buzzed, very loudly.

Christine was already out of her bedroom, fully dressed.

‘Christine the police are-’

‘I know, I know!’ she said. ‘Good morning Robert!’ Her face looked strained, but not frightened. She went to the intercom and buzzed the door open.

Rob pulled on his boots. Seconds later the police were in the flat-in the sitting room-and in Christine’s face.

The dapperly-suited man was courteous, wellspoken, faintly sinister and barely thirty years old. He gazed curiously at Rob. ‘You must be?’

‘Rob Luttrell.’

‘The British journalist?’

‘Well, American, but I live in London…’

‘Perfect. This is most convenient.’ The officer smiled as if he had been given an unexpectedly large cheque. ‘We are here to interview Miss Meyer about the terrible murder of her friend, Franz Breitner. But we would also like to talk with you, similarly. Perhaps afterwards?’

Rob nodded. He had anticipated a meeting with the police, but he felt oddly guilty being cornered here: in Christine’s flat, at 9 a.m. The policeman was maybe playing on this guilt. His smile was suggestive and superior. He sidled to the desk, then flicked another supercilious glance at Rob. ‘My name is Officer Kiribali. As we wish to speak with Miss Meyer first, in private, it would be beneficial if you could step outside for an hour or so?’

‘Well, OK…’

‘But don’t go far. Just for one hour. Then we can proceed with you.’ Another serpentine smile. ’Is that agreeable, Mr Luttrell?’

Rob looked at Christine. She nodded unhappily. Rob felt more guilt: at leaving Christine alone with this creepy guy. But he had no choice. Grabbing his jacket, he left the flat.

He spent the following hour on a sweaty plastic seat in a noisy internet café, trying to ignore the grunting older man, in baker’s overalls, openly surfing lesbian porn on his right.

Rob worked the numbers from Breitner’s book. He stuck them in every search engine possible: juggling them and rearranging them. What could the numbers be? They surely were a clue, maybe the key. One likelihood was page numbers. But what book? And surely they went too high-1013?

The Turkish baker had finished his surfing. He brushed past Rob with a petulant expression. Rob squinted into his screen, and juggled the numbers again. What was all this about? Were they geographical coordinates? Calendar years? Carbon dates? Rob had no idea.

He was sensing that the best method of cracking a puzzle like this was to let it lie: to let the subconscious get to work. Like a computer humming away in a backroom. The idea had a good pedigree. Rob had once read about a scientist called Kekule who had been striving to establish the molecular structure of Benzene. Kekule toiled for months with no success. But then one night he dreamed of a snake with its tail in its mouth: an ancient symbol called an ouroboros.

Kekule then woke, recalled the dream, and realized his unconscious mind was speaking to him: the molecule for Benzene was a ring, a circle, like a snake chewing its tail. Like the ouroboros. Kekule rushed to the laboratory to test the hypothesis. The solution he had dreamed was correct in all parts.

That was how powerful the unconscious was. So maybe Rob had to leave the problem in the mental cellar for a while, to let it ferment. Then the solution to Breitner’s numbers might pop into his mind when he was thinking of something else: when he was showering, shaving, sleeping, or driving. Or being interviewed by the police…

The police! Rob checked his watch. An hour had passed. Thrusting his chair back, he paid the net café owner and walked swiftly to Christine’s flat.

One of the uniformed policemen opened the door. Christine was sitting on the sofa, dabbing at her eyes. The other constable was handing out tissues. Rob bristled.

‘Do not worry Mr Luttrell.’ Officer Kiribali was sitting on the desk, his legs neatly crossed at the ankle. His tone-of-voice was casual and presumptuous. ‘We are not Iraqis here. But Miss Meyer found talking of her friend’s death rather…discomfiting.’

Christine glanced warily at the policeman and Rob detected plenty of resentment in her expression. Then she walked to her bedroom and slammed the door shut.

Kiribali shot his dazzling white cuffs, and wafted a manicured hand across the sofa, gesturing Rob to sit down. The two other policemen were standing across the room. Mute and sentinel. Kiribali smiled down at Rob. ‘So you are a writer?’

‘Yes.’

‘How charming. I rarely get to meet genuine authors. This is such a primitive town. Because, you know, the Kurds…’ He sighed. ‘They are not exactly…scholars.’ He tapped his chin with his pen. ‘I studied English literature at Ankara. It is my private delight, Mr Luttrell.’

‘Well, I’m just a journalist.’

‘Hemingway was just a journalist!’

‘Really. I’m just a hack.’

‘But you are too modest. You are a gentlemen of letters. And of English letters, at that.’ Kiribali’s eyes were a very dark blue. Rob wondered if he was wearing tinted contacts. Vanity oozed from him. ‘I always liked American poets. The women in particular. Emily Dickinson. And Sylvia Plath? You know them?’ He looked at Rob, an inscrutable expression on his face. ‘An engine, an engine, chuffing me off like a Jew…I think I may well be a Jew!’ Kiribali smiled, urbanely. ‘Aren’t they some of the most frightening lines in literature?’

Rob didn’t know what to say. He didn’t want to discuss poetry with a policeman.

Kiribali sighed. ‘Another time, maybe.’ He waggled the pen between his fingers. ‘I only have a few questions. I am aware you did not witness the alleged murder. Consequently…’

And so the interview proceeded. It was brief to the point of perfunctory. Almost pointless. Kiribali barely noted Rob’s answers, one of the policemen turned a tape recorder on and off, in an apathetic way. Then Kiribali concluded with some more personal inquiries. He seemed more interested in Rob’s relationship with Christine. ‘She is a Jewess, is she not?’

Rob nodded. Kiribali smiled, contentedly, as if his biggest problem had been solved, then he laid the pen down. Resting it precisely in line with the edge of the desk. He clicked his fingers, the somnolent constables stirred; and the three policemen walked to the door. Pausing at the threshold, Kiribali asked Rob to tell Christine that she might be required for further questions, at ‘some point in the future’. And then he was gone, with a final noxious waft of cologne.

Rob swivelled. Christine was standing in the bedroom doorway, looking cool and relaxed again in white shirt and khakis.

‘What a total wanker.’

Christine shrugged acceptantly. ‘Peut-être. He was just doing his job.’

‘He made you cry.’

‘Talking about Franz. Yes…I haven’t done that for a few days.’

Rob picked his jacket up. Then he put it down. He stared at Breitner’s notebook on the desk. He didn’t know what to do now. He didn’t know where he was headed or where this story was going; he just knew he was involved and possibly even endangered. Or was that paranoia? Rob stared at the picture on the wall. The unusual tower. Christine followed his gaze.