"I have been sitting in the box in conversation with the stranger."
"All the time?"
"Yes. He took precautions against being seen."
"Who was he?"
"I have no idea," I responded, still puzzled by the man's demand.
"I had better, perhaps, explain at once to mademoiselle that we are agents of police," he said, with a smile, "and that the movements of the individual who met you and chatted with you so affably are of the greatest interest to us."
"Then you know who he is?" I exclaimed quickly.
"Yes. We have discovered that."
"Who is he?"
"Unfortunately, it is not our habit to give details of any case on which we are engaged until it is completed."