He took the small box from his pocket and revealed the contents. ‘Exhibit B. He passed this on too. And listen, will you, to the story the doctor had to tell.’

Bonnefoye listened, wholly involved in the story, turning the gold amulet between his fingers, his face showing fascination and revulsion at the ugliness of the features of the god. Finally: ‘The God of Evil, you say? Brother of the good God, Osiris? And his murderer?’

‘Yes. Set was worshipped throughout Egypt for many centuries. But as a god of goodness. He and Osiris were peas in a pod. But then, apparently, he turned to wickedness and was struck off everyone’s calling list. His subsequent career plumbed the depths of iniquity, you might say. A recognizable myth – in many cultures you find a reference to the evil obverse of a coin. Cain and Abel . . . And take Lucifer – after all, the name means “Bringer of Light”. He started off on the side of the angels. Was one of the angels.’

Bonnefoye picked up the crime novel and began to riffle through its pages. ‘Have you seen it yet? The link between your book and your amulet?’

Joe shook his head.

‘Good stories, these! The theme still fires the imagination, you see? Down the centuries and right through into the twentieth.’

Joe didn’t quite see.

‘The evil Fantômas is pursued in each story by a police inspector from my own outfit, the Brigade Criminelle, no less. Inspector Juve, the good guy! And no prizes for guessing Juve’s secret identity. He’s the long-lost twin brother of Fantômas.’

‘Juve and Fantômas, Osiris and Set?’

‘Two minutes, boys! Heavens! Is this how you waste your time? The Série Noire? Don’t you have enough real life crime to occupy your time? And who’s your ugly friend? Not sure I want him in my drawing room.’

‘He’s the man we’re looking for, Maman, and who’s looking for us! Let me introduce you – he’s the God of Evil. And our nameless killer I think now has – according to Joe – an identity. Let’s call him Set, shall we?’

Madame Bonnefoye considered for a moment and then said soberly: ‘Well, if Set comes calling, he’ll run into some fire-power! Your Lebel, Jean-Philippe, the pistol I see the Commander has on his right hip, the Luger Sir George has tucked in his upper left-hand inside pocket and my soup ladle. Come to table now!’

After a long and delicious meal, Jean-Philippe’s mother herded the men back into the salon with coffee and brandy, closed the door on them and began to clatter her way through the clearing up.

Sir George put on an instant show of affability and frank co-operation. ‘Now – I’m sure you chaps must have a question or two of your own to . . .’ He was expansive, he was slightly wondering why they had held off for so long from questioning him. He knew he was cornered.

‘Indeed, we do, George, and this time you’re not ducking them,’ said Joe firmly. ‘People’s lives – including, I do believe, your own – depend on your answers. So you must stop all this bluffing and circumlocution and come clean. I will know if you’re lying. Now, I have a list of questions to put to you.’

Sir George nodded.

Joe decided to catch him off balance by launching an easy throw but from an unexpected quarter. Start them on the easy questions; establish a rhythm of truthful responses and the slight hesitation before a lie is told will be picked up by a keen ear.

‘John Pollock?’ he said. ‘Or Jack Pollock – whichever you prefer. Tell us about him.’

‘Cousin Jack? Oh, very well. Son of my father’s very much younger sister, my Aunt Jane, who married a man called Pollock. Only son: John Eugene. He was never a friend, you understand. Twenty-year age gap. Looks on me more as an uncle. Little Jackie! A delightful child! Clever boy and with the Jardine good looks! He must be in his mid-thirties by now. He’s working in Paris, as you remember from Fourier’s notes. He was keen on a diplomatic career when he came out of the army and I was able to put his name in front of someone who was, in turn, able to give him a leg up. Find him a niche, you might say. And they haven’t regretted it. Doing well, by all accounts. Haven’t seen him since a year or two after the war ended. 1921? Possibly. I remember he wasn’t looking too sharp then – recuperating in London. But he had a good war. Quite the hero, in his way.’

‘Your cousin sends his regards and promises he’ll be in touch.’

‘Good. Good. I look forward to that.’

‘I’m afraid we’ll have to tell him any meeting between the two of you will have to be put on hold. Officially you’re in the custody of the Police Judiciaire in a lock-up somewhere on the island. No one but the three of us knows you’re here and that’s how it must remain until we’ve cleared you.’

‘Very well. Sensible precaution. He’ll be the first to understand and approve. Very security-minded, naturally. Next?’

‘Now, sir.’ Joe gathered his thoughts. The next bit was not so straightforward. ‘I’m hoping you feel able to supply us with the name of someone who witnessed your appearance at the theatre and can vouch for the fact that you were in your place across the width of the hall when the murder occurred – assuming it to have happened during the finale?’

‘Yes, I do. Been thinking about it. Racking the old brain, you know. And the name’s come back to me: Wilberforce Jennings.’

‘Who?’ Joe was startled. This was not what he was expecting. He’d been leading George to expand on the information he had slid into – or allowed to escape into – the conversation in Fourier’s office. Joe’s mind was running on a beautiful and unscrupulous woman with a penchant for Campari-soda. And murder and blackmail and extortion and deceit. But here was Wilberforce Jennings stealing the spotlight.

‘Old school chum. “Willie”, we called him. I was surprised to see him. You know how you gaze around the audience to see if there’s anyone you know – well, there was. Jennings. The most frightful little creep, I remember, and I may have completely misidentified him, but he was in the sixth row of the stalls at the end of the row. No idea whether he recognized me. You could always ask, I suppose. If you can find him. He may have allowed his gaze to rest on me in the concluding moments.’

‘When he could be looking at la belle Josephine and a hundred chorus girls wearing not so much as a bangle between them? Worth a try, I suppose. You never know your luck,’ said Joe doubtfully. ‘Can you oblige, Bonnefoye?’

‘Easy. We have access to records of every foreigner using accommodation in the city. There are about six hotels the English prefer to use. We’ll try them first.’

‘And now, George, we’ve got you in your box . . . The chairs – pulled into a companionable huddle . . . the tray of convivial drinks served and consumed. Tell us about your mystery guest. Who was she? Why are you twisting about in an effort to keep her identity from Fourier?’

Irritated by George’s dogged silence, he tried a full assault. ‘Alice Conyers paid you a visit, did she? Yes, I knew she’d survived. Though I had no idea she was in France.’

‘It’s hard to imagine, eh, Joe? You’re expecting your cousin and there bobs up at your elbow a girl you thought had died in terrible circumstances five years ago. I was never more surprised! She seemed well and happy and sent you her fond regards.’

‘She has good reason to remember me with fondness,’ said Joe bitterly. ‘But why did she show herself to you? I always thought the two of you were pretty thick but . . . all the same . . .’ Too late he heard the tetchiness amounting to jealousy in his voice. ‘A risky manoeuvre on her part, I’d have thought,’ he said more firmly. ‘You could have arrested her!’

‘I did. She escaped.’ George was breezily defiant.

Joe snorted in exasperation. ‘Sir, are you saying you had the woman in your grasp and you let her loose?’