“Was Charles Turold showing you the marks when I found you in the other room?” he asked with a keen glance.

Mr. Brimsdown’s admission of that fact was coupled with an assurance that the young man had shown him the marks because he was convinced of Sisily’s innocence.

Barrant dismissed young Turold’s opinions about the case with an impatient shake of the head.  “Who told him about the marks?” he said.

It was the thought which had occurred to Mr. Brimsdown at the time, but he did not say so then.  “How did you discover them?” he asked.

“When I was examining the body.  But Charles Turold had no reason to examine the body.  Perhaps Dr. Ravenshaw told him.  I must ask him.”

“It is a terrible and ghastly crime,” said Mr. Brimsdown, in an effort to turn the mind of his companion in another direction.  “There is something about it that I do not understand—­some deep mystery which has not yet been fathomed.  Was it really his daughter?  If so, how did she escape from the room and leave the door locked inside?  Escape from these windows is plainly impossible.”

He crossed to the window, and stood for a moment looking down at a grey sea tossing in futile restlessness.  After an interval he said—­

“Do you suspect Thalassa as well?”

The detective looked at him with a cautious air:  “Why do you ask that?” he said, with some restraint in his tone.

“It might account ... for certain things.”

Barrant shook his head in a way which was more noncommittal than negative.  He wanted to ascertain what the lawyer thought, but he was not prepared to reveal all his own thoughts in return.

“Do you think that Robert Turold invented this story about his marriage?” he asked suddenly.

“For what purpose?”

“He did not want his daughter to succeed him in the title.  His announcement about the previous marriage strikes me as just a little too opportune.  Where are the proofs?”

“You would not talk like that if you had known Robert Turold,” said the lawyer, turning away from the window.  “He was too anxious to gain the title to jeopardize the succession by concocting a story of a false marriage.  He had proofs—­I have not the slightest doubt of that.  I believe he had them in the house when he made his statement to the family.”

“Then where are they now?”

“They may have been stolen.”

“For what reason?”

“By some one interested.”

“The person most interested is Robert Turold’s daughter,” said Barrant thoughtfully.  “That supposition fits in with the theory of her guilt.  Robert Turold is supposed to have kept valuable papers in that old clock on the wall, which was found on the floor that night.  Apparently he staggered to it during his dying moments and pulled it down on top of him.  For what purpose?  His daughter may have guessed that the proofs of her illegitimacy were kept there, and tried to get them.  Her father sought to stop her, and she shot him.”