s 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.

CHAPTER IX. THE ELECTRICIAN

When Muller reached the house where Mrs. Klingmayer lived he ordered the
cabman to wait and hurried up to the widow's little apartment. He had
the key to Leopold Winkler's room in his own pocket, for Mrs. Klingmayer
had given this key to Commissioner von Riedau at the latter's reque