Next night I was back again in Hanover, having stopped in Berlin to pick up a friend of mine upon whose discretion I could rely implicitly--a retired member of the detective force named Hartwieg. Together we started to watch the movements of the mysterious Polish musician, and to our surprise we found that he had three friends, one of them a furrier living in the Burgstrasse, who visited him regularly each evening. They always arrived at the same hour, and generally left about eleven o'clock. Through five days we kept watch, alternately closely shadowing the man who called himself Sembach, and becoming acquainted with his friends, most of whom seemed of a very queer set. There was no doubt that Minckwitz and the two young women were associates of some criminal gang, and, further, I was staggered one evening to watch the arrival at the house of a young man whom I recognized as Brosch, an under-valet of the Emperor's at the Neues Palais. For what reason had he come from Potsdam? He remained there till noon on the following day. When he emerged, accompanied by Minckwitz, the pair went into the city, and we followed, when, curiously enough, I came face to face with Von Pappenheim's sister, who was apparently there for the same purpose as myself! Happily she was too intent in her conversation with Minckwitz, whom she met as though accidentally, to notice my presence. Then, at last, the musician raised his hat and left her, rejoining the young man Brosch. The pair went to a bookshop in the Herschelstrasse, and presently, when they came forth again, Brosch was carrying a good-sized volume wrapped in brown paper. My curiosity was aroused, therefore I went into the shop, made a purchase, and learned from the shopman that the younger of the pair had purchased a well-known German reference-book, Professor Nebendahl's "Dictionary of Classical Quotations." Strange that such a book should be purchased by an under-valet! Leaving the detective Hartwieg to watch, I took the next train back to Potsdam, where I was fortunate enough to find the Emperor giving audience to the Imperial Chancellor. At the conclusion of the audience I sought, and was accorded, a private interview, at which I recalled His Majesty's anxiety to ascertain something regarding the man Minckwitz. "Well--and have you found him?" asked the Emperor very eagerly. I replied in the affirmative. Then he told me something which held me breathless, for, unlocking a drawer, he showed me an anonymous letter of warning he had received, a letter which, posted in Paris, stated that an attempt was to be made upon his life, and hinting that the Crown-Prince might be aware of it. "Of course," he laughed, "I do not regard it seriously, but I thought we ought to know the whereabouts of this man Minckwitz, who is probably an anarchist." "Will Your Majesty leave the matter entirely in my hands?" I suggested. "The police must not be informed."