“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—someone would have heard something. Then who locked and unlocked Lady Donaldson’s door that night while she herself lay dead?
“Someone in the house, I tell you—someone who left no trace—someone against whom there could be no suspicion—someone 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?
XVIII
The Theft at the English Provident Bank
“That question of motive is a very difficult and complicated one at times,” said the man in the corner, leisurely pulling off a huge pair of flaming dog-skin gloves from his meagre fingers. “I have known experienced criminal investigators declare, as an infallible axiom, that to find the person interested in the committal of the crime is to find the criminal.
“Well, that may be so in most cases, but my experience has proved to me that there is one factor in this world of ours which is the mainspring of human actions, and that factor is human passions. For good or evil passions rule this poor humanity of ours. Remember, there are the women! French detectives, who are acknowledged masters in their craft, never proceed till after they have discovered the feminine element in a crime; whether in theft, murder, or fraud, according to their theory, there is always a woman.
“Perhaps the reason why the Phillimore Terrace robbery was never brought home to its perpetrators is because there was no woman in any way connected with it, and I am quite sure, on the other hand, that the reason why the thief at the English Provident Bank is still unpunished is because a clever woman has escaped the eyes of our police force.”
He had spoken at great length and very dictatorially. Miss Polly Burton did not venture to contradict him, knowing by now that whenever he was irritable he was invariably rude, and she then had the worst of it.
“When I am old,” he resumed, “and have nothing more to do, I think I shall take professionally to the police force; they have much to learn.”
Could anything be more ludicrous than the self-satisfaction, the abnormal conceit of this remark, made by that shrivelled piece of mankind, in a nervous, hesitating tone of voice? Polly made no comment, but drew from her pocket a beautiful piece of string, and knowing his custom of knotting such an article while unravelling his mysteries, she handed it across the table to him. She positively thought that he blushed.
“As an adjunct to thought,” she said, moved by a conciliatory spirit.
He looked at the invaluable toy which the young girl had tantalisingly placed close to his hand: then he forced himself to look all round the coffee-room: at Polly, at the waitresses, at the piles of pallid buns upon the counter. But, involuntarily, his mild blue eyes wandered back lovingly to the long piece of string, on which his playful imagination no doubt already saw a series of knots which would be equally tantalising to tie and to untie.
“Tell me about the theft at the English Provident Bank,” suggested Polly condescendingly.
He looked at her, as if she had proposed some mysterious complicity in an unheard-of crime. Finally his lean fingers sought the end of the piece of string, and drew it towards him. His face brightened up in a moment.
“There was an element of tragedy in that particular robbery,” he began, after a few moments of beatified knotting, “altogether different to that connected with most crimes; a tragedy which, as far as I
