‘The Magic Flute’, Leigh said.

Arno nodded. ‘The new opera had its premiere performance in Vienna at the end of September 1791. It was received with rapturous enthusiasm by the public and the critics, and played to packed theatres night after night.’

‘It was the most successful thing Mozart had ever done,’ Leigh added.

‘Yes, it should have been the start of a new era for him,’ Arno replied. ‘And it was welcomed by his fellow Masons as a new hope for their Craft. But it was the last opera he would ever compose. Within less than three months, he was dead.’

‘Wait a minute,’ Ben said. ‘Leigh, didn’t you tell me that Mozart had been murdered by the Masons because he’d given away their secrets in The Magic Flute?’

‘That’s what I thought-’

‘Well, that doesn’t make sense, does it?’ Ben continued. ‘If Mozart was becoming this great new hope for the Masons, their public relations man at a time when they needed him most, then why kill him?’

Arno smiled. ‘You are right. This theory is completely illogical. Likewise, the fact that after Mozart’s death his fellow Masons gave his widow Constanze a great deal of moral and financial support makes nonsense of the idea that he was murdered by his own.’ Arno turned to Leigh. ‘Your brother had noticed these inconsistencies early on in the course of his research. Oliver knew that there was no satisfactory explanation for the strange and sudden death of Mozart.’

‘Unless he wasn’t murdered at all,’ Ben said. ‘How do we know there’s any truth in this murder conspiracy theory?’

‘The official cause of death was acute rheumatic fever,’ Arno replied. ‘However, many of those around him at the time found the circumstances of his passing highly suspicious. Towards the end of his life, Mozart often expressed his conviction that he would be poisoned one day-yet the scholars have never bothered to examine this properly. His elder son, Carl Thomas Mozart, also had strong suspicions that his father had died by foul means. The body displayed unusual characteristics consistent with death by poisoning.’ Arno shrugged. ‘Based on the medical records of the time, nobody can disprove that Mozart was poisoned. But the single most important piece of evidence is the letter itself.’

‘What does it say?’ Leigh asked.

Arno looked surprised. ‘You have not seen it?’

‘I had Oliver’s copy but it got burnt,’ Leigh said. ‘All I’ve seen of it are a few fragments.’

‘But surely your father showed it to you?’

‘Professor, I was only nineteen years old. I had other things on my mind.’ She glanced at Ben. ‘I don’t remember much about it.’

‘I see…’ Arno paused and scratched his chin. ‘So you are not familiar with the Order of Ra, to which the letter refers?’

Ben remembered it from Oliver’s notes. He thought for a moment. ‘Ra as in the Egyptian sun god Ra?’ he asked.

Leigh turned to stare at him.

He caught her look. ‘Theology,’ he said. ‘Student days.’

‘You studied Theology?’

‘It was a long time ago.’

Arno smiled. ‘You are correct, and many of the ceremonies and traditions of Freemasonry can be traced back to ancient Egypt. But Ra also means King. It is sometimes written as Re, and is the origin of the word Rex in Latin and your English words regal and royal’.

‘So what was this Order of Ra?’ Ben asked.

‘The Order of Ra was originally a small and obscure Masonic Lodge,’ Arno answered. ‘Their members were largely aristocratic and pro-royalist, and they gave their group a name that would reflect their political leanings: for them it signified the Order of the King. They were far divorced from the growing republican spirit within Freemasonry, and became increasingly allied to the establishment powers as the perceived threat from the Masons grew. While Freemasonry stood for freedom, democracy and the people, the Order of Ra stood for the complete opposite. They were warmongers, fervent capitalists, an agency founded to aid elitist governments in suppressing the people.’

‘A kind of rogue splinter group, then,’ Ben said.

‘Exactly,’ Arno replied. ‘And an extremely powerful one, with lofty connections. The Order of Ra meddled in many political intrigues, not least of which was to put pressure on the Emperor of Austria to ban the rest of Freemasonry outright, even on pain of execution.’

‘Let me get this right,’ Leigh said. ‘You’re suggesting that the Order of Ra killed Mozart because he was popularizing Freemasonry through his opera The Magic Flute?’

The professor’s eyes glittered. ‘That is what I believe. And I believe the letter proves it. Mozart was a potential threat to them. If he could restore public support for Freemasonry, he could be dangerous. He was a rising star, a meteoric talent just beginning to shine. The massive success of The Magic Flute had given him great prestige. He had only just been appointed to a prominent post at the Court, and had the Emperor’s ear.

‘But his enemies were rising up too. By 1791 the members of the Order of Ra were fast becoming a major executive branch of the secret services. Their agents were brutal, violent and ruthless, and their Grand Master was none other than the Head of the Austrian secret police. He was a callous murderer, sworn to destroy the Masons.’

Ben was about to ask the man’s name, but Arno carried on.

‘By 1794, just three years after Mozart’s death, Masonry in Austria had effectively been obliterated. Many murders were committed-some openly, some less openly. Poisoning was one of their most common means, and would have been the most suited to disposing of someone of Mozart’s increasing celebrity status. They had to be careful. Other, more obscure, Masons met with a far more violent end. Gustav Lutze, for instance.’

‘Who was he?’ Leigh asked.

‘He was the man Mozart wrote the letter to,’ Arno said. ‘A member of the same Viennese Masonic Lodge, Beneficence. Mozart was writing to warn him of the growing danger. The letter is dated the sixteenth of November 1791, and is perhaps the last one he ever wrote. Of course, the so-called experts believe that his last surviving letter was the one he wrote to his wife on the fourteenth of October, while she was away taking the waters in Baden. Idiots. In any case, the letter never reached its destination; it was too late.’

‘What happened to Lutze?’ Ben asked.

‘He was found dead on the twentieth of November 1791. Just two weeks before Mozart’s death. Lutze had been tied to a post and tortured to death. Disembowelled, his tongue hacked out. The secret police blamed a Freemason for the crime.’

Ben stood up, reaching in his pocket. ‘Professor, I want you to take a look at something.’ He took out the CD-ROM in its plastic case. ‘May I?’ He walked around the desk and loaded the disc into the computer.

‘What is this?’ Arno asked as the machine whirred into life.

‘Something Oliver saw the night he died,’ Ben said. ‘Just watch.’

Arno blinked bemusedly at the screen. Leigh stayed in her chair, not wanting to see the video-clip again.

The images began to play. Ben watched the professor’s face as the clip went on. The victim was brought out. The macabre spectacle unfolded.

The old man’s eyes widened and his cheeks drained of colour. He pointed a trembling finger at the screen.

Ben reached across and paused the clip just before the victim’s tongue was cut out. In the frozen image the man’s face was contorted in terror. The blade was held high in the air, where it caught the candlelight.

Arno slumped in his chair. ‘Dio mio,’ he breathed, and wiped a trickle of sweat from his brow with a handkerchief. ‘So it is true.’

‘What’s true, Professor?’ Leigh asked.

Arno was about to reply when the window behind him exploded into the room and blood spattered across the computer screen.