Balthazar smiled as he took the old man’s hand. His grip was firm, his skin dry. ‘Thank you. You remember me?’ he asked.

Erno nodded. ‘Of course. You asked a lot of questions. You were curious. Unusually so. Balthazar is an unusual name. And you are a Gypsy. I wish more of your people would come to visit us. We have a lot in common.’

Balthazar said, ‘We do. And one day, when we have a museum, I will welcome you.’

Erno smiled. ‘I very much look forward to that, Detective. Let me know if I can ever help.’

‘I will. Thank you,’ said Balthazar. Erno Hartmann was as sincere, and as engaging as he remembered.

Erno said, ‘I was reading about the shooting yesterday. A shooting with a sub-machine gun.’ He shook his head slowly. ‘It’s unbelievable. This is usually a safe city. I read that you were there. You were not hurt?’

Balthazar shook his head. ‘No. I was on the other side of Klauzal Square when it started.’

Erno fixed Balthazar with his gaze. ‘Is it connected? Elad’s disappearance? Gunfire outside his apartment building?’

‘And mine. I live on the same floor as the flat he stayed in.’

‘Ah, then you know his landlady, Eva neni, the palacsinta queen.’

Balthazar smiled. ‘Yes, very well.’

‘A wonderful lady. We went to school together. She must be worried sick.’

‘She is.’

Erno, Balthazar could see, was watching him, not with hostility but a kind of curiosity. It was a common reaction when everyday Hungarians encountered a black-haired, brown-eyed detective who was obviously a Gypsy. But Balthazar sensed something more in Hartmann’s appraising glance. The elderly man was assessing him, Balthazar knew. His instinct told him that Hartmann could be a valuable ally.

Balthazar decided to trust him. ‘To answer your question, yes, I think all these things are connected.’

Erno gestured to Balthazar. ‘Which is why you are here. And I am glad you are. Come, walk with me. You are not in a hurry, Detective?’ It wasn’t so much a question as a statement.

Balthazar glanced at his watch. Almost 9.45 a.m. There was a busy day ahead. He was due to meet Ilona Mizrachi, the Israeli cultural attaché, at a café on Klauzal Street, at eleven o’clock. After that he would meet Anastasia at her office on Falk Miksa Street, then join up with Sandor Takacs and head to the Kerepesi Way cemetery, for the memorial service for the Librarian in the afternoon. He was not going to mourn, but to observe. Karoly Bardossy, the CEO of Nationwide, would be there, and Karoly Bardossy, Balthazar sensed, was somehow key to all this. But for now Balthazar had some time. And Erno Hartmann, he sensed, would not be rushed.

‘No, I am not in a hurry,’ said Balthazar.

‘Good, then we can take a few minutes,’ said Hartmann. ‘We are very proud of our museum. And no, in case you are wondering, I am no longer the director, I retired when the renovation started. The new director is thirty-five and a graduate from several universities. She has a master’s degree in library and archival studies.’ He shook his head in mild wonder. ‘Who knew that such diplomas existed? But she is kind enough to keep me on as a consultant.’

Kind enough and smart enough, Balthazar thought as he looked around, increasingly impressed. He had been inside plenty of renovated properties in Budapest – the city was enjoying a building boom, but had never seen a transformation like this from shabby post-communist to London or New York gallery chic. The floor was lined by white-and-grey marble tiles, the walls were a pristine shade of white and massive skylights had been placed in the ceiling where the sunlight poured in. The exhibits were no longer jumbled together, but each was mounted on a cream board, and displayed in a pristine, floor-to-ceiling glass cabinet.

‘It’s beautiful. So light and modern,’ said Balthazar.

‘Thank you. We had some generous benefactors. The government, some private companies. One firm in particular has been very generous. But the most important thing is that our new prime minister has been very supportive. She has substantially increased our budget, enough to pay for all the renovations, these lovely galleries. And we are branching out, into – what’s the word? – micro-history. We will soon have our first open-air exhibition outside the museum, in Klauzal Square, featuring local characters, past and present. Miss Bardossy was the guest of honour at our recent reception – you may have seen the media coverage.’

‘I did. Not everyone was pleased.’

‘What can we do, Detective? We have a very troubled history and some of our compatriots are still struggling with that,’ said Erno, shrugging. ‘It will take time. But some good things are happening as well. I’ll take you through to Elad’s office in a few minutes, but first, please indulge an elderly man.’

He led Balthazar to the first display case, pointing out a Torah scroll from the sixteenth century from Miskolc in eastern Hungary, a giant brass candelabra from the nineteenth century, and cloths to cover the bread on Friday night for Shabbat from Budapest. The adjacent display case held a medieval gravestone from a now-vanished Jewish cemetery in the Castle District, the Hebrew letters now just faded shadows.

They walked over to a long, curved ram’s horn to be blown on the New Year, both ends wrapped in ornate silver plate embossed with Hebrew script. There was no one else around – the museum did not open till 10 a.m. so they had the place to themselves.

‘A shofar,’ said Balthazar.

Hartmann looked surprised. ‘I’m impressed. Did you remember that from your visit?’

‘Yes, but also because my ex-wife was Jewish. We came to Dohany Street synagogue for New Year and for the Day of Atonement.’

‘Then you know something about our traditions. The shofar was supposed to be the grandest in the whole Habsburg empire. Grander than what they had in Vienna, that was the main thing. They blew it here, every year in the Great Synagogue, until the end of the First World War.’

For a moment he looked into the distance. ‘My grandfather fought for the empire in that war. He was awarded a medal for charging a British machine gun nest. His brother was killed in action. When things got bad here, their military records helped, for a while. And then they didn’t any more.’ Hartmann blinked. ‘Now come with me, Detective. You have not travelled all this way to listen to an old man’s reminiscences.’

The two men stepped toward a door marked Private: Staff Only, and into the main administrative offices. These had also been renovated in the same bright, modern style as the museum’s public space. Six pale-wood desks were spread around the room, each with a new monitor and keyboard and an Italian leather office chair in front.

Most of the desks were piled high with papers, files and books. Erno and Balthazar were the only ones present. One desk, in the far corner, was almost bare, with no computer or keyboard, although a modern-looking laser printer stood on a small table nearby. Three books were neatly arranged on one corner, next to a plain white mug. Balthazar walked over and looked more closely. He turned to Hartmann. ‘Is this Elad’s desk?’

Erno nodded. ‘That’s his, yes.’

‘His computer?’

‘He worked on a laptop. He did not leave it here overnight.’ Erno gestured at the printer. ‘That’s his as well. A very fancy machine. Better than ours. It even scans and prints out photographs.’

Balthazar stood by the desk and put on a pair of blue latex gloves. The books were all works of Jewish history, about the war and the Holocaust. He picked them up, one by one, held them by their spines and flicked through the pages. Nothing fell out. He placed them back where they had been, then reached for the mug. He held it to his nose. It smelled of coffee. The desk had two drawers.

He pulled them open – both were empty. He ran his hands around the inside of the drawers, slid them back and forth, shook them from side to side, felt around the underside of the desk then checked the cushion and legs of Elad’s chair. There was nothing there. Which made sense – Elad had hidden the important stuff on the memory stick, which Vivi was now going through.

Balthazar turned to Hartmann. ‘Nobody should touch this desk. I will send over someone from the local station to put crime scene tape around it.’

Erno looked alarmed. ‘You think something happened here?’

‘It’s possible, but on balance no, I don’t think so. You have very high security here, CCTV everywhere, a direct link to the local police station and police headquarters. All the buildings’ entrances and exits are covered. It would be very hard to get someone out of here without being noticed.’

Balthazar walked over to the window and looked out. The museum was part of the Great Synagogue complex on Dohany Street and was high on the government’s list of protected buildings. Two uniformed police officers were standing by the synagogue entrance, and two more were patrolling nearby, all huddled in their padded winter jackets. Across the street, a police car was parked near the bus stop.

Leaning against the wall, by the entrance to an apartment building, a tall middle-aged man Balthazar recognised as part of the city’s undercover squad stood smoking. Bela Siklosi, Balthazar knew, was much more alert than he appeared. The two men had worked together several times and sometimes met for a beer.

Another member of the undercover squad sat on a bench near the synagogue entrance, not reading the newspaper he was holding in front of him. Security, Balthazar was sure, had been boosted since Elad’s disappearance.

But who was the young woman in her twenties wearing a black padded jacket and a blue hat, standing by the nearby bus stop, with a view of the entrance to the museum, looking at a map? She looked almost familiar – then he realised she had been twenty yards ahead of him for much of his walk from Dob Street to Dohany Street.

That was at least thirty minutes ago. At that moment she walked over to one of the policemen, gave him a big smile, pointed at the map and asked a question. Balthazar could see that she was nodding at the answer, but was also looking from side to side.

Balthazar turned to Erno. ‘Would you excuse me for a moment? I need to make a call.’

‘Of course. Is it private? Should I leave?’

Balthazar thought for a moment then shook his head. ‘No, it’s fine. Come here. You might enjoy this. Watch the girl with the map, talking to the policeman.’

The two men stood by the window. Balthazar picked up his mobile and scrolled through the numbers until he found Bela’s then pressed dial. Balthazar spoke rapidly. Bela looked up at the window, nodded at Balthazar and Erno, then walked over to the young woman. He said something first to the uniformed policeman, showed his wallet. The uniformed cop stepped back.