“No,” he said. “You have not told me, for instance, why you installed Nurse Leatheran in the house.”
Dr. Leidner looked completely bewildered.
“But I have explained that. It is obvious. My wife’s nervousness—her fears . . .”
Poirot leaned forward. Slowly and emphatically he wagged a finger up and down.
“No, no, no. There is something there that is not clear. Your wife is in danger, yes—she is threatened with death, yes. You send—not for the police—not for a private detective even—but for a nurse! It does not make the sense, that!”
“I—I—” Dr. Leidner stopped. The colour rose in his cheeks. “I thought—” He came to a dead stop.
“Now we are coming to it,” Poirot encouraged him. “You thought—what?”
Dr. Leidner remained silent. He looked harassed and unwilling.
“See you,” Poirot’s tone became winning and appealing, “it all rings what you have told me, except for that. Why a nurse? There is an answer—yes. In fact, there can be only one answer. You did not believe yourself in your wife’s danger.”
And then with a cry Dr. Leidner broke down.
“God help me,” he groaned. “I didn’t. I didn’t.”
Poirot watched him with the kind of attention a cat gives a mouse-hole—ready to pounce when the mouse shows itself.
“What did you think then?” he asked.
“I don’t know. I don’t know. . . .”
“But you do know. You know perfectly. Perhaps I can help you—with a guess. Did you, Dr. Leidner, suspect that these letters were all written by your wife herself?”
There wasn’t any need for him to answer. The truth of Poirot’s guess was only too apparent. The horrified hand he held up, as though begging for mercy, told its own tale.
I drew a deep breath. So I had been right in my half-formed guess! I recalled the curious tone in which Dr. Leidner had asked me what I thought of it all. I nodded my head slowly and thoughtfully, and suddenly awoke to the fact that M. Poirot’s eyes were on me.
“Did you think the same, nurse?”
“The idea did cross my mind,” I said truthfully.
“For what reason?”
I explained the similarity of the handwriting on the letter that Mr. Coleman had shown me.
Poirot turned to Dr. Leidner.
“Had you, too, noticed that similarity?”
Dr. Leidner bowed his head.
“Yes, I did. The writing was small and cramped—not big and generous like Louise’s, but several of the letters were formed the same way. I will show you.”
From an inner breast pocket he took out some letters and finally selected a sheet from one, which he handed to Poirot. It was part of a letter written to him by his wife. Poirot compared it carefully with the anonymous letters.
“Yes,” he murmured. “Yes. There are several similarities—a curious way of forming the letter s, a distinctive e. I am not a handwriting expert—I cannot pronounce definitely (and for that matter, I have never found two handwriting experts who agree on any point whatsoever)—but one can at least say this—the similarity between the two handwritings is very marked. It seems highly probable that they were all written by the same person. But it is not certain. We must take all contingencies into mind.”
He leaned back in his chair and said thoughtfully: “There are three possibilities. First, the similarity of the handwriting is pure coincidence. Second, that these threatening letters were written by Mrs. Leidner herself for some obscure reason. Third, that they were written by someone who deliberately copied her handwriting. Why? There seems no sense in it. One of these three possibilities must be the correct one.”
He reflected for a minute or two and then, turning to Dr. Leidner, he asked, with a resumal of his brisk manner: “When the possibility that Mrs. Leidner herself was the author of these letters first struck you, what theory did you form?”
Dr. Leidner shook his head.