“‘By Jove, you’re wonderful,’ I said.

“He smirked, and called my attention to the various artistic touches which I might have missed.

“‘Wonderful,’ I said to myself again.  ’Nobody could possibly guess.’

“I peered into the hall.  It was empty.  We hurried across to the library; he got into the passage and made off.  I went back to the bedroom, collected all his discarded clothes, did them up in a bundle and returned with them to the passage.  Then I sat down in the hall and waited.

“You heard the evidence of Stevens, the maid.  As soon as she was on her way to the Temple in search of Mark, I stepped into the office.  My hand was in my side-pocket, and in my hand was the revolver.

“He began at once in his character of Robert—­some rigmarole about working his passage over from Australia; a little private performance for my edification.  Then in his natural voice, gloating over his well-planned retaliation on Miss Norris, he burst out, ‘It’s my turn now.  You wait.’  It was this which Elsie heard.  She had no business to be there and she might have ruined everything, but as it turned out it was the luckiest thing which could have happened.  For it was the one piece of evidence which I wanted; evidence, other than my own, that Mark and Robert were in the room together.

“I said nothing.  I was not going to take the risk of being heard to speak in that room.  I just smiled at the poor little fool, and took out my revolver, and shot him.  Then I went back into the library and waited—­just as I said in my evidence.

“Can you imagine, Mr. Gillingham, the shock which your sudden appearance gave me?  Can you imagine the feelings of a ‘murderer’ who has (as he thinks) planned for every possibility, and is then confronted suddenly with an utterly new problem?  What difference would your coming make?  I didn’t know.  Perhaps none; perhaps all.  And I had forgotten to open the window!

“I don’t know whether you will think my plan for killing Mark a clever one.  Perhaps not.  But if I do deserve any praise in the matter, I think I deserve it for the way I pulled myself together in the face of the unexpected catastrophe of your arrival.  Yes, I got a window open, Mr. Gillingham, under your very nose; the right window too, you were kind enough to say.  And the keys —­yes, that was clever of you, but I think I was cleverer.  I deceived you over the keys, Mr. Gillingham, as I learnt when I took the liberty of listening to a conversation on the bowling-green between you and your friend Beverley.  Where was I?  Ah, you must have a look for that secret passage, Mr. Gillingham.

“But what am I saying?  Did I deceive you at all?  You have found out the secret—­that Robert was Mark—­and that is all that matters.  How have you found out?  I shall never know now.  Where did I go wrong?  Perhaps you have been deceiving me all the time.  Perhaps you knew about the keys, about the window, even about the secret passage.  You are a clever man, Mr. Gillingham.