Suddenly he bent down, examining a dark discolored bruise on the dead woman's arm.
He straightened himself up again.
There was a strange catlike gleam in his eyes that certain close associates of his would have recognized.
He left the room quickly and went downstairs.
Battle and a subordinate were at the telephone.
The latter laid down the receiver and said,
"He hasn't come back, sir."
Battle said, "Despard. I've been trying to get him.
There's a letter for him with the Chelsea postmark all right."
Poirot asked an irrelevant question.
"Had Doctor Roberts had his breakfast when he came here?"
Battle stared.
"No," he said, "I remember he mentioned that he'd come out without it."
"Then he will be at his house now.
We can get him."
"But why?"
But Poirot was already busy at the dial. Then he spoke.
"Doctor Roberts?
It is Doctor Roberts speaking?
Mais oui, it is Poirot here.
Just one question.
Are you well acquainted with the handwriting of Mrs. Lorrimer?"
"Mrs. Lorrimer's handwriting?
I - no, I don't know that I'd ever seen it before."
"Je vous remercie."
Poirot laid down the receiver quickly.
Battle was staring at him.
"What's the big idea, Monsieur Poirot?" he asked quietly.
Poirot took him by the arm.
"Listen, my friend.
A few minutes after I left this house yesterday, Anne Meredith arrived.
I actually saw her going up the steps, though I was not quite sure of her identity at the time.
Immediately after Anne Meredith left Mrs. Lorrimer went to bed.
As far as the maid knows, she did not write any letters then, and, for reasons which you will understand when I recount to you our interview, I do not believe that she wrote those three letters before my visit.
When did she write them, then?"
"After the servants had gone to bed?" suggested Battle.
"That is possible, yes, but there is another possibility - that she did not write them at all."
Battle whistled.
"My God, you mean -"
The telephone trilled.
The sergeant picked up the receiver.
He listened a minute, then turned to Battle.
"Sergeant O'Connor speaking from Despard's flat, sir.
There's reason to believe that Despard's down at Wallingford-on-Thames."
Poirot caught Battle by the arm.
"Quickly, my friend.
We, too, must go to Wallingford.
I tell you I am not easy in my mind.
This may not be the end.
I tell you again, my friend, this young lady, she is dangerous."