“There were no footprints on the grass edge?”

Poirot nodded.

“Exactly. Lord Mayfield, he fancies he sees a shadow. Then there comes the robbery and he is sure—but sure! It is no longer a fancy—he actually saw the man. But that is not so. Me, I do not concern myself much with footprints and such things but for what it is worth we have that negative evidence. There were no footprints on the grass. It had rained heavily this evening. If a man had crossed the terrace to the grass this evening his footprints would have shown.”

Sir George said, staring: “But then—but then—”

“It brings us back to the house. To the people in the house.”

He broke off as the door opened and Lord Mayfield entered with Mr. Carlile.

Though still looking very pale and worried, the secretary had regained a certain composure of manner. Adjusting his pince-nez he sat down and looked at Poirot inquiringly.

“How long had you been in this room when you heard the scream, monsieur?”

Carlile considered.

“Between five and ten minutes, I should say.”

“And before that there had been no disturbance of any kind?”

“No.”

“I understand that the house party had been in one room for the greater part of the evening.”

“Yes, the drawing room.”

Poirot consulted his notebook.

“Sir George Carrington and his wife. Mrs. Macatta. Mrs. Vanderlyn. Mr. Reggie Carrington. Lord Mayfield and yourself. Is that right?”

“I myself was not in the drawing room. I was working here the greater part of the evening.”

Poirot turned to Lord Mayfield.

“Who went up to bed first?”

“Lady Julia Carrington, I think. As a matter of fact, the three ladies went out together.”

“And then?”

“Mr. Carlile came in and I told him to get out the papers as Sir George and I would be along in a minute.”

“It was then that you decided to take a turn on the terrace?”

“It was.”

“Was anything said in Mrs. Vanderlyn’s hearing as to your working in the study?”

“The matter was mentioned, yes.”

“But she was not in the room when you instructed Mr. Carlile to get out the papers?”

“No.”

“Excuse me, Lord Mayfield,” said Carlile. “Just after you had said that, I collided with her in the doorway. She had come back for a book.”

“So you think she might have overheard?”

“I think it quite possible, yes.”

“She came back for a book,” mused Poirot. “Did you find her her book, Lord Mayfield?”

“Yes, Reggie gave it to her.”

“Ah, yes, it is what you call the old gasp—no, pardon, the old wheeze—that—to come back for a book. It is often useful!”

“You think it was deliberate?”

Poirot shrugged his shoulders.

“And after that, you two gentlemen go out on the terrace. And Mrs. Vanderlyn?”

“She went off with her book.”

“And the young M. Reggie. He went to bed also?”

“Yes.”