"The next day—namely, the 25th—she tries to dispose of a pair of earrings to Mr. Campbell; she fails, and decides to go to London, where she has a better chance. Sir James Fenwick did not think it desirable to bring forward witnesses to prove what I have since ascertained is a fact, namely, that on the 27th of October, three days before her arrest, Miss Crawford crossed over to Belgium, and came back to London the next day. In Belgium, no doubt, Lady Donaldson's diamonds, taken out of their settings, calmly repose at this moment, while the money derived from their sale is safely deposited in a Belgian bank."
"But then, who murdered Lady Donaldson, and why?" gasped Polly.
"Cannot you guess?" he queried blandly. "Have I not placed the case clearly enough before you? To me it seems so simple. It was a daring, brutal murder, remember. Think of one who, not being the thief himself, would, nevertheless, have the strongest of all motives to shield the thief from the consequences of her own misdeed: aye! and the power too—since it would be absolutely illogical, nay, impossible, that he should be an accomplice."
"Surely——"
"Think of a curious nature, warped morally, as well as physically—do you know how those natures feel? A thousand times more strongly than the even, straight natures in everyday life. Then think of such a nature brought face to face with this awful problem.
"Do you think that such a nature would hesitate a moment before committing a crime to save the loved one from the consequences of that deed? Mind you, I don't assert for a moment that David Graham had any intention of murdering Lady Donaldson. Tremlett tells him that she seems strangely upset; he goes to her room and finds that she has discovered that she has been robbed. She naturally suspects Edith Crawford, recollects the incidents of the other night, and probably expresses her feelings to David Graham, and threatens immediate prosecution, scandal, what you will.
"I repeat it again, I dare say he had no wish to kill her. Probably he merely threatened to. A medical gentleman who spoke of sudden heart failure was no doubt right. Then imagine David Graham's remorse, his horror and his fears. The empty safe probably is the first object that suggested to him the grim tableau of robbery and murder, which he arranges in order to ensure his own safety.
"But remember one thing: no miscreant was seen to enter or leave the house surreptitiously; the murderer left no signs of entrance, and none of exit. An armed burglar would have left some trace—some one would have heard something. Then who locked and unlocked Lady Donaldson's door that night while she herself lay dead?
"Some one in the house, I tell you—some one who left no trace—some one against whom there could be no suspicion—some one who killed without apparently the slightest premeditation, and without the slightest motive. Think of it—I know I am right—and then tell me if I have at all enlisted your sympathies in the author of the Edinburgh Mystery."
He was gone. Polly looked again at the photo of David Graham. Did a crooked mind really dwell in that crooked body, and were there in the world such crimes that were great enough to be deemed sublime?