'I must know who I am to arrest, and on what counts.'
'Quite so, mon ami Hale; I did not say you were to make an arrest, but merely warned you to be prepared. If you have time now to listen to the disclosures, I am quite at your service. I promise you there are some original features in the case. If, however, the present moment is inopportune, drop in on me at your convenience, previously telephoning so that you may know whether I am there or not, and thus your valuable time will not be expended purposelessly.'
With this I presented to him my most courteous bow, and although his mystified expression hinted a suspicion that he thought I was chaffing him, as he would call it, official dignity dissolved somewhat, and he intimated his desire to hear all about it then and there. I had succeeded in arousing my friend Hale's curiosity. He listened to the evidence with perplexed brow, and at last ejaculated he would be blessed.
'This young man,' I said, in conclusion, 'will call upon me at six on Wednesday afternoon, to receive his second five shillings. I propose that you, in your uniform, shall be seated there with me to receive him, and I am anxious to study Mr. Macpherson's countenance when he realises he has walked in to confront a policeman. If you will then allow me to cross-examine him for a few moments, not after the manner of Scotland Yard, with a warning lest he incriminate himself, but in the free and easy fashion we adopt in Paris, I shall afterwards turn the case over to you to be dealt with at your discretion.'
'You have a wonderful flow of language, Monsieur Valmont,' was the officer's tribute to me. 'I shall be on hand at a quarter to six on Wednesday.'
'Meanwhile,' said I, 'kindly say nothing of this to anyone. We must arrange a complete surprise for Macpherson. That is essential. Please make no move in the matter at all until Wednesday night.'
Spenser Hale, much impressed, nodded acquiescence, and I took a polite leave of him.
The question of lighting is an important one in a room such as mine, and electricity offers a good deal of scope to the ingenious. Of this fact I have taken full advantage. I can manipulate the lighting of my room so that any particular spot is bathed in brilliancy, while the rest of the space remains in comparative gloom, and I arranged the lamps so that the full force of their rays impinged against the door that Wednesday evening, while I sat on one side of the table in semi-darkness and Hale sat on the other, with a light beating down on him from above which gave him the odd, sculptured look of a living statue of Justice, stern and triumphant. Anyone entering the room would first be dazzled by the light, and next would see the gigantic form of Hale in the full uniform of his order.
When Angus Macpherson was shown into this room he was quite visibly taken aback, and paused abruptly on the threshold, his gaze riveted on the huge policeman. I think his first purpose was to turn and run, but the door closed behind him, and he doubtless heard, as we all did, the sound of the bolt being thrust in its place, thus locking him in.