“What have I withheld?” she asked defiantly.

“You have confessed that you asked Sir Charles to be at the gate at ten o’clock. We know that that was the place and hour of his death. You have withheld what the connection is between these events.”

“There is no connection.”

“In that case the coincidence must indeed be an extraordinary one. But I think that we shall succeed in establishing a connection, after all. I wish to be perfectly frank with you, Mrs. Lyons. We regard this case as one of murder, and the evidence may implicate not only your friend Mr. Stapleton but his wife as well.”

The lady sprang from her chair.

“His wife!” she cried.

“The fact is no longer a secret. The person who has passed for his sister is really his wife.”

Mrs. Lyons had resumed her seat. Her hands were grasping the arms of her chair, and I saw that the pink nails had turned white with the pressure of her grip.

“His wife!” she said again. “His wife! He is not a married man.”

Sherlock Holmes shrugged his shoulders.

“Prove it to me! Prove it to me! And if you can do so—!”

The fierce flash of her eyes said more than any words.

“I have come prepared to do so,” said Holmes, drawing several papers from his pocket. “Here is a photograph of the couple taken in York four years ago. It is indorsed ‘Mr. and Mrs. Vandeleur,’ but you will have no difficulty in recognizing him, and her also, if you know her by sight. Here are three written descriptions by trustworthy witnesses of Mr. and Mrs. Vandeleur, who at that time kept St. Oliver’s private school. Read them and see if you can doubt the identity of these people.”

She glanced at them, and then looked up at us with the set, rigid face of a desperate woman.

“Mr. Holmes,” she said, “this man had offered me marriage on condition that I could get a divorce from my husband. He has lied to me, the villain, in every conceivable way. Not one word of truth has he ever told me. And why—why? I imagined that all was for my own sake. But now I see that I was never anything but a tool in his hands. Why should I preserve faith with him who never kept any with me? Why should I try to shield him from the consequences of his own wicked acts? Ask me what you like, and there is nothing which I shall hold back. One thing I swear to you, and that is that when I wrote the letter I never dreamed of any harm to the old gentleman, who had been my kindest friend.”