“Oh, quite—quite—” Miss Lawson looked bewildered. She stared vacantly at Poirot. She went on. “But—I’m sorry—I’m sure it’s very stupid of me—but why should she write to you? I understand—in fact, I think you said so—that you are a detective. You’re not a—a doctor, too? Or a faith healer, perhaps?”
“No, I am not a doctor—nor a faith healer. But, like the doctor, I concern myself sometimes with so-called accidental deaths.”
“With accidental deaths?”
“With so-called accidental deaths, I said. It is true that Miss Arundell did not die—but she might have died!”
“Oh, dear me, yes, the doctor said so, but I don’t understand—”
Miss Lawson sounded still bewildered.
“The cause of the accident was supposed to be the ball of the little Bob, was it not?”
“Yes, yes, that was it. It was Bob
’s ball.”
“Oh, no, it was not Bob’s ball.”
“But, excuse me, M. Poirot, I saw it there myself—as we all ran down.”
“You saw it—yes, perhaps. But it was not the cause of the accident. The cause of the accident, Miss Lawson, was a dark-coloured thread stretched about a foot above the top of the stairs!”
“But—but a dog couldn’t—”
“Exactly,” said Poirot quickly. “A dog could not do that—he is not sufficiently intelligent—or, if you like, he is not sufficiently evil…A human being put that thread in position….”
Miss Lawson’s face had gone deadly white. She raised a shaking hand to her face.
“Oh, M. Poirot—I can’t believe it—you don’t mean—but that is awful—really awful. You mean it was done on purpose?”
“Yes, it was done on purpose.”
“But that’s dreadful. It’s almost like—like killing a person.”
“If it had succeeded it would have been killing a person! In other words—it would have been murder!”
Miss Lawson gave a little shrill cry.
Poirot went on in the same grave tone.
“A nail was driven into the skirting board so that the thread could be attached. That nail was varnished so as not to show. Tell me, do you ever remember a smell of varnish that you could not account for?”
Miss Lawson gave a cry.
“Oh, how extraordinary! To think of that! Why, of course! And to think I never thought—never dreamed—but then, how could I? And yet it did seem odd to me at the time.”
Poirot leant forward.
“So—you can help us, mademoiselle. Once again you can help us. C’est épatant!”
“To think that was it! Oh, well, it all fits in.”
“Tell me, I pray of you. You smelt varnish—yes?”
“Yes. Of course, I didn’t know what it was. I thought—dear me—is it paint—no, it’s more like floor stain, and then, of course, I thought I must have imagined it.”
“When was this?”