“We must find out.”  He spoke loudly, as if with the idea that a firm utterance lessened the tremendous difficulty of that performance.

“What can we do?” Her tone was hopeless enough.

“Let me think.”  He fiddled with the planchette on the table as though he had some notion of invoking the shade of Robert Turold to answer the question.  “Had your father any enemy?  Did he fear anybody?”

She raised thoughtful eyes to his in reply.

“My father feared nobody,” she said, “at least, I do not think so.  Nobody had any real influence over him except Thalassa.”

“What sort of an influence?”

“It is difficult to describe,” she hesitatingly answered.  “Thalassa could take liberties which nobody else would have dared.  He used to go into his room at any time.  Sometimes I have awakened late at night and heard the murmur of their voices coming from my father’s study.”

“Anything else?” he said, looking at her keenly.

“There was never any question of Thalassa leaving us,” she went on.  “Wherever we went, and we were always going to some fresh part of England about the title, Thalassa went also.  Perhaps it was because he had known him for so long that my father allowed Thalassa to do things which nobody else could do.  Thalassa used to sneer about the title, and say no good would come of it.  They had a quarrel once, long, long ago.  I was a very little girl at the time, and I can just remember it,” she added dreamily.

She was apparently unconscious of the significance of these revelations, but they made a deep impression upon Charles.  There was something expectant and cruel in his face as he listened—­the aroused instinct of the hunter.  He addressed her—­

“This bears out what I have believed all along.  Thalassa knows about the murder.  He is mixed up in it in some way.”

“Oh, why do you think that?” she exclaimed, clasping her hand in distress.

“Why?” he echoed.  “Because your father was not the man to stand insolence from Thalassa or anybody else unless he had to.  Thalassa must have had him under his thumb in some way.  Why did I not know of this before?  It’s clear enough now.  Thalassa, even if he did not commit the murder—­”

“He did not,” she said quickly.  “He left the house with me, so he could not have done it.”

“Then he knows who did.  He and your father shared some secret together—­some dreadful secret which brought about your father’s death.  That is one reason why Thalassa will not speak—­because he is implicated in this mystery, whatever it is.”

“No, no.  He is keeping silence because of me—­I feel sure.  I made him promise not to tell.”

Charles Turold shook his head decidedly.  “He may have more than one reason for keeping silent,” he said with a swift flash of intuition.  “If it is as you say, he is shielding himself as well as you.  If your father was killed while Thalassa was out of the house that night, Thalassa knows who did it.”