Markwick had stolen them! I now recollected, quite distinctly, that at the moment I entered he had his hands behind his back endeavouring to conceal something.
I started forward to go and inform the police, but remembering that ere long I should place Grindlay in possession of all the tangled chain of facts, I rang the bell for Saunders instead.
“What time did Lady Fyneshade arrive,” I asked, when he had responded to my summons.
“About half an hour before you returned, sir.”
“Were they alone in this room the whole time?”
“Yes, sir. Her ladyship went to the piano and played several songs.”
His words convinced me. Mabel had strummed on the piano in order to drown the sound of the breaking open of the cabinet.
For what reason, I strove to imagine, had Markwick obtained the letters? How, indeed, could he have known their hiding-place, or that they were in my possession?
I felt absolutely certain that, having satisfied themselves of my absence, they had entered in order to obtain possession of those half-charred letters, and that on my unexpected return Mabel, in order to cover their confusion, had skillfully concocted an object for their visit. She had tricked me cleverly, and although half mad with anger at my loss, I could not help admiring her extraordinary self-possession and the calm circumstantial manner in which she had lied to me.
Business London had drawn its whirling fevered day to a close when I entered one of the bare waiting-rooms at New Scotland Yard, and sent my card to Inspector Grindlay. I had not long to wait, for in a few minutes he came in, greeting me bluffly with a hearty hand-shake, expressing pleasure that I had called.