“That can be done in a very few words, Mr. Holmes. The letter—for it was a letter from a foreign potentate—was received six days ago. It was of such importance that I have never left it in my safe, but have taken it across each evening to my house in Whitehall Terrace, and kept it in my bedroom in a locked despatch-box. It was there last night. Of that I am certain. I actually opened the box while I was dressing for dinner and saw the document inside. This morning it was gone. The despatch-box had stood beside the glass upon my dressing-table all night. I am a light sleeper, and so is my wife. We are both prepared to swear that no one could have entered the room during the night. And yet I repeat that the paper is gone.”
“What time did you dine?”
“Half-past seven.”
“How long was it before you went to bed?”
“My wife had gone to the theatre. I waited up for her. It was half-past eleven before we went to our room.”
“Then for four hours the despatch-box had lain unguarded?”
“No one is ever permitted to enter that room save the house-maid in the morning, and my valet, or my wife’s maid, during the rest of the day. They are both trusty servants who have been with us for some time. Besides, neither of them could possibly have known that there was anything more valuable than the ordinary departmental papers in my despatch-box.”
“Who did know of the existence of that letter?”
“No one in the house.”
“Surely your wife knew?”