“‘The unknown is a man of taste and of some fortune,’ he said, ’not the sort of man to send a stupid peasant to guard the woman he loves.  So I am not content to believe, with Mr. Sears, that the servant is a boor.  I believe him, instead, to be a very clever ruffian.  I believe him to be the protector of his master’s honor, or, let us say, of his master’s property, whether that property be silver plate or the woman his master loves.  Last night, after Lord Arthur had gone away, the servant was left alone in this house with Lord Chetney and Madame Zichy.  From where he sat in the hall, he could hear Lord Chetney bidding her farewell; for, if my idea of him is correct, he understands English quite as well as you or I. Let us imagine that he heard her entreating Chetney not to leave her, reminding him of his former wish to marry her, and let us suppose that he hears Chetney denounce her, and tell her that at Cairo he has learned of this Russian admirer—­the servant’s master.  He hears the woman declare that she has had no admirer but himself, that this unknown Russian was, and is, nothing to her, that there is no man she loves but him, and that she cannot live, knowing that he is alive, without his love.  Suppose Chetney believed her, suppose his former infatuation for her returned, and that, in a moment of weakness, he forgave her and took her in his arms.  That is the moment the Russian master has feared.  It is to guard against it that he has placed his watch-dog over the Princess, and how do we know but that, when the moment came, the watch-dog served his master, as he saw his duty, and killed them both?  What do you think?’ Lyle demanded.  ’Would not that explain both murders?’

“I was only too willing to hear any theory which pointed to anyone else as the criminal than Arthur, but Lyle’s explanation was too utterly fantastic.  I told him that he certainly showed imagination, but that he could not hang a man for what he imagined he had done.

“‘No,’ Lyle answered, ’but I can frighten him by telling him what I think he has done, and now when I again question the Russian servant I will make it quite clear to him that I believe he is the murderer.  I think that will open his mouth.  A man will at least talk to defend himself.  Come,’ he said, ’we must return at once to Scotland Yard and see him.  There is nothing more to do here.’

“He arose, and I followed him into the hall, and in another minute we would have been on our way to Scotland Yard.  But just as he opened the street-door a postman halted at the gate of the garden, and began fumbling with the latch.

“Lyle stopped, with an exclamation of chagrin.