"I presume that you did so on instructions from Tranter?"
"Yes."
"Evidently he shadowed me to Paddington Station, as I expected he would, and decided to remove you in case I should get on the right track."
"He sent me an urgent message," she said, "saying that a great disaster hung over his head, and that I must go away without leaving any trace. He told me where to go, and promised to come to me and explain."
"He knew that it was only you who could give any proof against him?"
"After forty years," she returned, with a touch of bitterness, "he ought to have known that I should not betray him."
"Even if one had told you of those three dreadful crimes that he had committed, and that an innocent man was accused of the last one?"
She locked her hands together.
"Don't ask me," she cried. "I don't know what I should have done."
"He foresaw that problem," said Monsieur Dupont. "His sanity was, as you have said, wonderful. But the sanity of madness is always wonderful—that is why madmen are such superb criminals. It is only a madman who can be really sane. Although I allowed him to see that I knew already something of the truth, he never betrayed himself by even a tremor. He had all the grand egotism of the born criminal. His disguise was impenetrable. He was never sure how far my knowledge went, but not a sign of anxiety did he ever show. We played a game of cross purposes. I used him, under the pretense of requiring his assistance, to keep him by my side, and in the hope that as he saw me draw nearer to him step by step, he would break down. He, on his side, allowed himself to be used in order to keep watch on my moves, and safeguard himself against them, as he did in the case of Miss Masters. He dared not leave me. In all my conversations with him, I placed him more and more at his wit's end to know how much I really knew. As much from curiosity as from anything, I instructed him to discover the secret of Mr. Copplestone's house, for I was convinced that it did contain an interesting secret. He was quite willing to make the attempt. It did not promise to lead me any nearer to him. He little thought when he went—and I had little thought when I sent him—that he was going to his own undoing."