“Mrs. Lyons,” said I as I rose from this long and inconclusive interview, “you are taking a very great responsibility and putting yourself in a very false position by not making an absolutely clean breast of all that you know. If I have to call in the aid of the police you will find how seriously you are compromised. If your position is innocent, why did you in the first instance deny having written to Sir Charles upon that date?”

“Because I feared that some false conclusion might be drawn from it and that I might find myself involved in a scandal.”

“And why were you so pressing that Sir Charles should destroy your letter?”

“If you have read the letter you will know.”

“I did not say that I had read all the letter.”

“You quoted some of it.”

“I quoted the postscript. The letter had, as I said, been burned and it was not all legible. I ask you once again why it was that you were so pressing that Sir Charles should destroy this letter which he received on the day of his death.”

“The matter is a very private one.”

“The more reason why you should avoid a public investigation.”

“I will tell you, then. If you have heard anything of my unhappy history you will know that I made a rash marriage and had reason to regret it.”

“I have heard so much.”

“My life has been one incessant persecution from a husband whom I abhor. The law is upon his side, and every day I am faced by the possibility that he may force me to live with him. At the time that I wrote this letter to Sir Charles I had learned that there was a prospect of my regaining my freedom if certain expenses could be met. It meant everything to me - peace of mind, happiness, self-respect - everything. I knew Sir Charles’s generosity, and I thought that if he heard the story from my own lips he would help me.”

“Then how is it that you did not go?”

“Because I received help in the interval from another source.”

“Why, then, did you not write to Sir Charles and explain this?”

“So I should have done had I not seen his death in the paper next morning.”

The woman’s story hung coherently together, and all my questions were unable to shake it. I could only check it by finding if she had, indeed, instituted divorce proceedings against her husband at or about the time of the tragedy.

It was unlikely that she would dare to say that she had not been to Baskerville Hall if she really had been, for a trap would be necessary to take her there, and could not have returned to Coombe Tracey until the early hours of the morning. Such an excursion could not be kept secret. The probability was, therefore, that she was telling the truth, or, at least, a part of the truth. I came away baffled and disheartened. Once again I had reached that dead wall which seemed to be built across every path by which I tried to get at the object of my mission. And yet the more I thought of the lady’s face and of her manner the more I felt that something was being held back from me. Why should she turn so pale? Why should she fight against every admission until it was forced from her? Why should she have been so reticent at the time of the tragedy? Surely the explanation of all this could not be as innocent as she would have me believe. For the moment I could proceed no farther in that direction, but must turn back to that other clue which was to be sought for among the stone huts upon the moor.