Hanaud handed it to the Commissaire.

“It will be necessary to keep that,” he said.

It was a thin piece of strong whipcord.  It was the same kind of cord as that which had been found tied round Mme. Dauvray’s throat.  Hanaud opened the door and turned back to the nurse.

“We will send for a cab for Mlle. Vauquier.  You will drive with her to her door.  I think after that she will need no further help.  Pack up a few things and bring them down.  Mlle. Vauquier can follow, no doubt, now without assistance.”  And, with a friendly nod, he left the room.

Ricardo had been wondering, through the examination, in what light Hanaud considered Helene Vauquier.  He was sympathetic, but the sympathy might merely have been assumed to deceive.  His questions betrayed in no particular the colour of his mind.  Now, however, he made himself clear.  He informed the nurse, in the plainest possible way, that she was no longer to act as jailer.  She was to bring Vauquier’s things down; but Vauquier could follow by herself.  Evidently Helene Vauquier was cleared.

CHAPTER VII

A STARTLING DISCOVERY

Harry Wethermill, however, was not so easily satisfied.

“Surely, monsieur, it would be well to know whither she is going,” he said, “and to make sure that when she has gone there she will stay there—­until we want her again?”

Hanaud looked at the young man pityingly.

“I can understand, monsieur, that you hold strong views about Helene Vauquier.  You are human, like the rest of us.  And what she has said to us just now would not make you more friendly.  But—­ but—­” and he preferred to shrug his shoulders rather than to finish in words his sentence.  “However,” he said, “we shall take care to know where Helene Vauquier is staying.  Indeed, if she is at all implicated in this affair we shall learn more if we leave her free than if we keep her under lock and key.  You see that if we leave her quite free, but watch her very, very carefully, so as to awaken no suspicion, she may be emboldened to do something rash—­or the others may.”

Mr. Ricardo approved of Hanaud’s reasoning.

“That is quite true,” he said.  “She might write a letter.”

“Yes, or receive one,” added Hanaud, “which would be still more satisfactory for us—­supposing, of course, that she has anything to do with this affair”; and again he shrugged his shoulders.  He turned towards the Commissaire.

“You have a discreet officer whom you can trust?” he asked.

“Certainly.  A dozen.”

“I want only one.”

“And here he is,” said the Commissaire.

They were descending the stairs.  On the landing of the first floor Durette, the man who had discovered where the cord was bought, was still waiting.  Hanaud took Durette by the sleeve in the familiar way which he so commonly used and led him to the top of the stairs, where the two men stood for a few moments apart.  It was plain that Hanaud was giving, Durette receiving, definite instructions.  Durette descended the stairs; Hanaud came back to the others.