‘Not only was Questing innocent of espionage but, if we are to believe his letter, he actually recognized and accused the real culprit, who adopted a threatening attitude and, by a species of blackmail, extracted an undertaking from Questing that he would not betray him. Questing suggests that when they parted they were mutually distrustful of one another, and I suggest that fright, rather than business, prompted his sudden decision to go to Australia. He felt himself to be in danger just as we now feel ourselves to be in danger and, in a figure that he himself might have used, he passed the buck to Mr Bell. I think he must have written that letter just before we left for the concert. I happened to pass his open door and saw him with his elbows squared on his table. As you know, some three hours later he was killed.’

‘Will you excuse me,’ said Gaunt. ‘I don’t want to be difficult but, as I’ve tried to point out before, I’ve been extremely upset by this unspeakably horrible affair and I’m afraid I just haven’t got the kind of mind that revels in post mortems. I’m sorry. I shall leave you to it.’

‘One moment, Mr Gaunt,’ said Falls. ‘You’re upset, I fancy, not so much by the knowledge that Questing died very horridly, as by the fear that you yourself might be implicated.’

‘I won’t have this!’ cried Gaunt, and sprang to his feet. ‘I resent this, bitterly.’

‘Do sit down. You see,’ said Mr Falls, looking amiably about him, ‘in spite of ourselves we are becoming the orthodox muster of suspects. Here is Mr Gaunt who quarrelled with Mr Questing because Mr Questing used his name as an advertisement, and because he pretended he was the author of a gift that Mr Gaunt himself had made.’

Barbara started galvanically. Gaunt began to accuse Dikon. ‘So I’ve got you to thank—’

‘No,’ said Falls. ‘My dear Gaunt, who but you could have made this gift? A quotation from Shakespeare on the card? Written by the shop assistant? You see I have heard all about it. And, if that was not enough, your very expressive face betrayed you most completely last night, when Questing spoke of her enchanting dress to Miss Barbara. You looked—please forgive the unhappy phrase—positively murderous. Was it not the memory of this that led you to conceal your subsequent quarrel with Questing? It seems to me you had quite a lot to agitate you when Questing was killed.’

‘I have explained to the point of hysteria that I was anxious to avoid publicity. Good God, who ever committed murder for such a motive? Sergeant Webley, I beg that you—’

‘I quite agree,’ said Falls. ‘Who ever did? May I pass on, for the moment, to another of our suspects? Mr Smith.’