It was striking eight as Muller came out of a caf?in the heart of the city. He had been in there but a few moments, for his purpose was merely to look through the Army lists of the current year. The result of his search proved the correctness of his conclusions.

There was a Lieutenant Theobald Leining in the single infantry regiment stationed at Marburg.

Muller took a cab and drove to the main telegraph office. He asked for the original of the telegram which had been sent that afternoon to the address; "Herbert Thorne, Hotel Danieli, Venice." This closed the circle of the chain.

The detective re-entered his waiting cab and drove back to Hietzing.

He told the driver to halt at the corner of the street on which fronted the Thorne mansion and to wait for him there. He himself walked slowly down the quiet Street and rang the bell at the iron gate.

"You come to this house again?" asked Franz, starting back in alarm when he saw who it was that had called him to the door.

"Yes, my good friend; I want to get into this house again. But not on false pretenses this time. And before you let me in you can go upstairs and ask Mrs. Bernauer if she will receive me in her own room - in her own room, mind. But make haste; I am in a hurry."The detective's tone was calm and he strolled slowly up and down in front of the gate when he had finished speaking.

The old butler hesitated a moment, then walked into the house.

When he returned, rather more quickly, he looked alarmed and his tone was very humble as he asked Muller to follow him.

When the detective entered Mrs. Bernauer's room the housekeeper rose slowly from the large armchair in front of her table. She was very pale and her eyes were full of terror. She made no move to speak, so Muller began the conversation. He put down his hat, brought up a chair and placed it near the window at which the housekeeper had been sitting. Then he sat down and motioned to her to do the same.

"You are a faithful servant, all too faithful," he began. "But you are faithful only to your master. You have no devotion for his wife.""You are mistaken," replied the woman in a low tone.

"Perhaps, but I do not think so. One does not betray the people to whom one is devoted."Mrs. Bernauer looked up in surprise. "What - what do you know?"she stammered.

Muller did not answer the question directly, but continued: "Mrs.

Thorne had a meeting recently with a strange man. It was not their first meeting, and somehow you discovered it. But before this last meeting occurred you spoke to the lady's husband about it, and it was arranged between you that you should give him a signal which would mean to him, 'Your wife is going to the meeting.' Mrs. Thorne did go to the meeting. This happened on Monday evening at about quarter past nine. Some one, who was in the neighbourhood by chance, saw a woman's figure hurrying through the garden, down to the other street, and a moment after this, the light of this lamp in your window was seen to go out. A hand had turned down the wick - it was your hand.

"This was the signal to Mr. Thorne. The mirrors over his desk reflected in his eyes the light he could not otherwise have seen as he sat by his own window. The signal, therefore, told him that the time had come to act. This same chance watcher, who had seen the woman going through the garden, had seen the lamp go out, and now saw a man's figure hurrying down the path the woman had taken.

The man as well as the woman came from this house and went in the direction of the lower end of the garden.

"A little while later a shot was heard, and the next morning Leopold Winkler was found with a bullet in his back. The crime was generally taken to be a murder for the sake of robbery. But you and I, and Mr. Herbert Thorne, know very well that it was not.

"You know this since Wednesday noon. Then it was that the idea suddenly came to you, falling like a heavy weight on your soul, the idea that Winkler might not have been killed for the sake of robbery, but because of the hatred that some one bore him. Then it was that you lost your appetite suddenly, that you drove into the city with the excuse of errands to do, in order to read the papers without being seen by any one who knew you. When you came home you searched everywhere in your master's room: you made an excuse for this search, but what you wanted to find out was whether he had left anything that could betray him. Your fright had already confused your mind.

You were searching probably for the weapon from which he had fired the bullet. You did not realise that he would naturally have taken it with him and thrown it somewhere into a ravine or river beside the railway track between here and Venice. How could you think for a moment that he would leave it behind him, here in his room, or dropped in the garden? But this was doubtless due to the confusion owing to your sudden alarm and anxiety - a confusion which prevented you from realising the danger of the two peculiarly hung mirrors in Mr. Thorne's room. These should have been taken away at once. This morning my sudden appearance at the garden gate prevented you from making an examination of the place of the murder. Your swoon, after I had spoken to you in the butler's room, showed me that you were carrying a burden too heavy for your strength. Finally, this afternoon, you drove to the main telegraph office in the city, as you thought that it would be safer to telegraph Mr. Thorne from there. Your telegram was very cleverly written. But you might have spared the last sentence, the request that Mr. Thorne should get the Viennese papers of these last days. Believe me, he has already read these papers. Who could be more interested in what they have to tell than he?"The housekeeper had sat as if frozen to stone during Muller's long speech. Her face was ashen and her eyes wild with horror. When the detective ceased speaking, there was dead silence in the room for some time. Finally Muller asked: "Is this what happened?" His voice was cutting and the glance of his eyes keen and sharp.