Roger laughed soothingly. "Just exercising my well - known powers. Whatever caused that scratch, my dear Colin, it wasn't, for instance, a pin. Look at it for yourself."
"Does it matter a tuppenny damn what caused it?"
"Not even a three - ha'penny one. It's just my regrettable curiosity. Don't tell me if it's anything terribly private."
"Why should it be private, you old rascal?"
"Well, it looks to me like a scratch from someone's fingernail. In fact, if I didn't know you so well, Colin, I should say you had been making a nuisance of yourself to a lady and got very properly scratched for your pains."
Roger's fly - fishing was rewarded. "Well, it was nothing of the sort," Colin said crossly, "and none but a mind like yours would have thought it was. If you're really so curious, I got it on a bit of broken glass."
"And where have you been playing with broken glass?" Colin grudgingly gave the commonplace particulars. He had broken a glass at the bar and hidden the pieces under the table.
CHAPTER VIII
THE CASE AGAINST ROGER SHERINGHAM
"I ACCEPT your explanation, Colin," Roger said judicially, leaning back against the railing that bordered the roof.
"The deuce you do, Roger. That's very kind of you."
"Don't get heated. I was only thinking that men have been hanged before now because their explanations weren't accepted. Many, many men, Colin."
"Have you brought me up here in the cold just to tell me that?"
"We'll go into the sun parlour, if you prefer it," Roger said kindly.
"I do prefer it. I've reached the age when I appreciate comfort." Colin Nicolson was an elderly and disillusioned twenty - eight.
They went down the steps to the sun parlour, switched on the light, and found two chairs. "Well, now, what's on your mind, Roger?" Colin asked when they were settled.
"Why should you think anything's on my mind?"
"I know the signs. You're like an old war horse that smells the powder. Surely you're not trying to wist this business into anything serious?"
"I should have thought," Roger said mildly, - that it was quite serious enough already."
"Huh!" Colin made a Scottish noise, expressive of any interpretation which its hearer might care to put on it.
Roger was minded to try a little experiment. "No, of course not. I was just thinking on what small points these cases depend. One single piece of evidence is enough to turn an apparently obvious case of suicide into a still more obvious case of murder, or an accident into a suicide, or what you will. As a student of crime yourself, Colin, can you pick out the vital piece of evidence in this case?"
"Vital, you mean, for suicide?"
"Yes."
Colin thought. "That she'd been talking about killing herself half the evening?"
"No, no, no. That's evidence the other way, if anything. No, I mean material evidence."
Colin pondered. "No, I'm blessed if I can."
"Well, everyone just takes it for granted that it was suicide. Why? No, I'll tell you. Because there's a piece of evidence which does actually prove it was suicide, but which in all probability no one has consciously realized. They've seen it, and they've absorbed it, but because it was part of the general picture of suicide they just take it for granted. Like you, not one of them could put a name to it. Can't you, Colin? It's something perfectly obvious."
"Do you mean the absence of any signs of violence?"
"No, but of course that is a point, too," Roger had to concede.
"Well, what is it, then?"
"Why, that chair on the ground below her, of course. You remember there was a chair lying on its side under the gallows?"
"Yes."
"Well, the presence of that chair proves that she wasn't lifted up into the noose, and it proves too that she did voluntarily put her own head in. Doesn't it?"
"Yes, I see what you mean. Very interesting, Roger. Yes, that's the important piece of evidence, without a doubt."
Roger nodded and lit a cigarette. His experiment had been successful. The human mind is apt to accept what it thinks ought to exist with such decision that it will even construct and imprint on the memory perfectly detailed pictures the originals of which never, in fact, did exist at all. Colin without doubt had looked several times, when they were on the roof just now, at the gallows. Underneath the gallows was a fallen chair. That fallen chair was a necessary detail in a stage set for suicide. Colin therefore perfectly remembered it being there while he was administering first - aid to Mrs. Stratton twenty minutes ago. The picture was firmly printed on his brain: a gallows with only two figures instead of three, and a fallen chair on the ground beneath the third crossbeam. It was impossible that the chair could not have been there twenty minutes ago. Colin remembered its presence perfectly. He would swear, with complete sincerity, not merely that he thought the chair was there when he first came out on the roof, but that it actually was there. And so would everyone else in the party. Roger never had been troubled by the smallest doubt that the addition of the chair to the picture would be noticed by a single person.
"And you think," Colin pursued, "that if the chair hadn't been there, the case would have smelt of murder?"
"I'd put it a little more strongly than that. I should say that murder would have been perfectly obvious." Roger was enjoying the irony of discussing fact as if it were wild hypothesis. It was a pity Colin could not appreciate the irony.
"Because she couldn't possibly have got her neck into the noose without either being lifted up or standing on something high enough?"
"Exactly. Do you agree?"
"Yes, I certainly do. This is very interesting, Roger."
"It's good exercise, to appreciate the importance of trifles," Roger said cautiously.
"And that's why you were so interested in my scratch?"
Roger laughed. If Colin only knew how near the wind he was sailing . . .
"Well, we can say that it amused me, by way of exercise, to pretend to myself that the chair never had been there at all, and therefore it was a case of murder; and there were you with a nice scratch on your hand, just such as I might have been looking for on one of the party, in that event."
"Well, well. But what motive could I have had for making away with the unfortunate woman? There's motive enough going about, I'll grant you, but not in my case. I'd never met her before this evening."
"But don't you see, that's precisely what would make the perfect murder," Roger said with enthusiasm. "It's motive, in ninety - nine cases out of a hundred, that really pins a murder on a certain individual. Without a motive, suspicion might never be directed towards him at all."
"Without a motive there'd be no murder." Colin was entering into the discussion with nearly as much interest as Roger himself, although to him it must have seemed almost preposterously academic.
"When I say without a motive, of course I mean without an apparent motive. But take this very instance. You apparently had no motive at all for Mrs. Stratton's death. That is to say, no material motive. But need a motive always be material? What about a spiritual one?"
"Well, what about a spiritual one?" said Colin, rather aggressively.
"De mortuis nil nisi verum. I see no reason why one shouldn't speak the truth about the dead. The woman was a pest. She was making a nuisance of herself to almost everyone she came in contact with, she was a real menace to the happiness of at least two people here tonight, and she was making her husband's life a misery to him. There were only two things that could be done to stop her: shut her up in a madhouse or polish her off. Unfortunately she wasn't quite insane enough to be certifiable; therefore only the second alternative remains. But not a one of the people who had a material motive for her removal had the moral guts to effect it.