‘This is very confusing. Should I understand that you believe him to have—’ Marco’s full lips seemed to frame and discard one or two words before they chose ‘—absconded?’

‘That is the Questore’s theory.’

‘But not yours?’ he asked quickly.

‘I have none.’

‘I conclude, Mr Alleyn, that your attendance here tonight, which must have followed your enrolment in today’s tour, is professional rather than recreational.’

‘Yes,’ Alleyn agreed cheerfully. ‘That’s about it. And now I mustn’t take up any more of your time. If—and the chances I believe are remote—if Mr Mailer should put in an appearance here—‘ Marco gave an ejaculation and a very slight wince ‘—Il Questore Valdarno and I would be most grateful if you would say nothing to him about this discussion. Simply telephone at once to—but the number is on the Questore’s card, I think.’

‘The Questore,’ said Marco in a hurry, ‘will I am sure appreciate that any kind of unpleasantness, here, in the restaurant, would be—’ he flung up his hands.

‘Unthinkable,’ Alleyn filled in. ‘Oh yes. It would all be done very tactfully and quite behind the scenes, you know.’

He held out his hand. Marco’s was damp and exceedingly cold.

‘But you think,’ he persisted, ‘you yourself think, isn’t it, that he will not come back?’

‘For what it’s worth,’ Alleyn agreed, ‘that’s my idea. Not, at any rate, of his own volition. Goodbye.’

On his way out he went to the telephone booth and rang Il Questore Valdarno, who reported that he had set up further inquiries but had no news. Mailer’s flat had been found. The porter said Mailer left it at about three o’clock and had not returned. The police briefly examined the flat, which seemed to be in order.

‘No signs of a sudden departure?’

‘None. Yet I am still persuaded—’

‘Signor Questore, may I ask you to add to the many favours you have already granted? I am not familiar with your police regulations and procedures but I understand you are less restricted than we are. Would it be possible to put a man in Mailer’s flat at once and could that man answer the telephone and make a careful note of any calls, if possible tracing their origin? I think it’s highly probable that Marco of La Gioconda will at this moment be trying to get him and will try again. And again.’

‘Marco! Indeed? But—yes of course. But—’

‘I have spoken to him. He was discreet but his reaction to the disappearance was interesting.’

‘In what way? He was distressed?’

‘Distress—yes. Not, I think, so much by Mailer’s disappearance as by the thought of his return. That prospect, unless I’m very much mistaken, terrifies him.’

‘I shall attend to this at once,’ said II Questore.

‘If Mailer is still missing tomorrow, would you allow me to have a look at his rooms?’