With this suspicion in his mind what Muller had learned from Knoll was of great value to him, at all events of great interest. Was it the housekeeper who had put out the light? For now Muller did not doubt for a moment that this sudden extinguishing of the lamp was a signal. He believed that Knoll had seen clearly and that he had told truly what he had seen. A lamp that is blown out by the wind flickers uneasily before going out. A sudden extinguishing of the light means human agency. And the lamp was lit again a few moments afterward and burned on steadily as before. A short time after the lamp had been put out the man had been seen going through the garden. And it could not have been much later before the shot was heard. This shot had been fired between the hours of nine and ten, for it was during this hour only that Knoll was in the garden house and heard the shot. But it was not necessary to depend upon the tramp's evidence alone to determine the exact hour of the shot.
It must have been before half past nine, or otherwise the janitor of No.1, who came home at that hour and lay awake so long, would undoubtedly have heard a shot fired so near his domicile, in spite of the noise occasioned by the high wind. There would have been sufficient time for Mrs. Bernauer to have reached the place of the murder between the putting out of the lamp and the firing of the shot. But perhaps she may have rested quietly in her room; she may have been only the inciter or the accomplice of the deed. But at all events, she knew something about it, she was in some way connected with it.
Muller drew a deep breath. He felt much easier now that he had arranged his thoughts and marshalled in orderly array all the facts he had already gathered. There was nothing to do now but to follow up a given path step by step and he could no longer reproach himself that he might have cast suspicion on an innocent soul. No, his bearing towards Mrs. Bernauer had not been sheer brutality. His instinct, which had led him so unerringly so many times, had again shown him the right way when he had thrust the accusation in her face.
Now that his mind was easier he realised that he was very hungry.
He drove to a restaurant and ordered a hasty meal.
"Beer, sir?' asked the waiter for the third time.
"No," answered Muller, also for the third time.
"Then you'll take wine, sir?" asked the insistent Ganymede.
"Oh, go to the devil! When I want anything I'll ask for it,"growled the detective, this time effectively scaring the waiter.
It did not often happen that a customer refused drinks, but then there were not many customers who needed as clear, a head as Muller knew he would have to have to-day. Always a light drinker, it was one of his rules never to touch a drop of liquor during this first stage of the mental working out of any new problem which presented itself. But soft-hearted as he was, he repented of his irritation a moment later and soothed the waiter's wounded feelings by a rich tip. The boy ran out to open the cab door for his strange customer and looked after him, wondering whether the man was a cranky millionaire or merely a poet. For Joseph Muller, by name and by reputation one of the best known men in Vienna, was by sight unknown to all except the few with whom he had to do on the police force. His appearance, in every way inconspicuous, and the fact that he never sought acquaintance with any one, was indeed of the greatest possible assistance to him in his work. Many of those who saw him several times in a day would pass him or look him full in the face without recognising him. It was only, as in the case of Mrs. Bernauer, the guilty conscience that remembered face and figure of this quiet-looking man who was one of the most-feared servants of the law in Austria.
