“Why should any one see him? We were all on the beach. I gather the Marshall child and Christine Redfern were down on Gull Cove out of the way. Captain Marshall was in his room in the hotel. Then who on earth was there to see him except possibly Miss Darnley.”

“Where was Miss Darnley?”

“Sitting up on the cutting at the top of the cliff. Sunny Ledge it’s called. We saw her there, Mr. Redfern and I, when we were rowing round the island.”

Colonel Weston said:

“You may be right, Miss Brewster.”

Emily Brewster said positively:

“I’m sure I’m right. When a woman’s neither more nor less than a nasty mess, then she herself will provide the best possible clue. Don’t you agree with me, M. Poirot?”

Hercule Poirot looked up. His eyes met her confident grey ones. He said:

“Oh, yes—I agree with that which you have just this minute said. Arlena Marshall herself is the best, the only clue, to her own death.”

Miss Brewster said sharply:

“Well, then!”

She stood there, an erect sturdy figure, her cool self-confident glance going from one man to the other.

Colonel Weston said:

“You may be sure, Miss Brewster, that any clue there may be in Mrs. Marshall’s past life will not be overlooked.”

Emily Brewster went out.

VI

Inspector Colgate shifted his position at the table. He said in a thoughtful voice:

“She’s a determined one, she is. And she’d got her knife into the dead lady, proper, she had.”

He stopped a minute and said reflectively:

“It’s a pity in a way that she’s got a cast-iron alibi for the whole morning. Did you notice her hands, sir? As big as a man’s. And she’s a hefty woman—as strong and stronger than many a man, I’d say….”

He paused again. His glance at Poirot was almost pleading.

“And you say she never left the beach this morning, M. Poirot?”

Slowly Poirot shook his head. He said:

“My dear Inspector, she came down to the beach before Mrs. Marshall could have reached Pixy Cove and she was within my sight until she set off with Mr. Redfern in the boat.”

Inspector Colgate said gloomily:

“Then that washes her out.”

He seemed upset about it.

VII

As always, Hercule Poirot felt a keen sense of pleasure at the sight of Rosamund Darnley.

Even to a bare police inquiry into the ugly facts of murder she brought a distinction of her own.

She sat down opposite Colonel Weston and turned a grave and intelligent face to him.

She said:

“You want my name and address? Rosamund Anne Darnley. I carry on a dressmaking business under the name of Rose Mond Ltd at 622 Brook Street.”

“Thank you, Miss Darnley. Now can you tell us anything that may help us?”

“I don’t really think I can.”

“Your own movements—”

“I had breakfast about nine thirty. Then I went up to my room and collected some books and my sunshade and went out to Sunny Ledge. That must have been about twenty-five past ten. I came back to the hotel about ten minutes to twelve, went up and got my tennis racquet and went out to the tennis courts, where I played tennis until lunchtime.”