hat he might have seen his master sitting at his desk, already
a corpse.

"He must have been dead when you came home. Don't you think the sound of
that shot would have wakened you?"

"Yes, sir, I think likely, sir," murmured Johann. "But if the murderer
could get into the house, how could he get into the apartment?"

"There must have been a third key of which you knew nothing," answered
Horn, turning to Muller again. "It's stranger still how Fellner
could have been shot, for the window-shutters were fastened and quite
uninjured, and both doors were locked on the inside."

As he said these words, Horn looked sharply at his subordinate; but
Muller's calm face did not give the slightest clue to his thoughts. The
experienced police commissioner was pleased and yet slightly angered at
this behaviour on the part of the detective. He knew that it was quite
possible that Muller had already formed a clear opinion about the case,
and that he was merely keeping it to himself. And yet he was glad to
see that the little detective had apparently learned a lesson from his
recent mistake concerning the death of Mrs. Kniepp--that he had somewhat
lost confidence in his hitherto unerring instinct, and did not care to
express any opinion until he had studied the matter a little closer. The
commissioner was just a little bit vain, and just a little bit jealous
of this humble detective's fame.

Muller shrugged his shoulders at the remark of his superior, and the
two men stood silent, thinking over the case, as the Chief of Police
appeared, accompanied by the doctor, a clerk, and two hospital
attendants. The chief commissioner received the report of what had
been discovered, while the corpse was laid on a bier to be taken to the
hospital.

Muller handed the commissioner his hat and cane and helped him into
his overcoat. Horn noticed that the detective himself was making
no preparations to go out. "Aren't you coming with us?" he asked,
astonished.

"I hope the gentlemen will allow me to remain here for a little while,"
answered Muller modestly.

"But you know that we will have to close the apartment officially," said
Horn, his voice sharpening in his surprise and displeasure.

"I do not need to be in these rooms any longer."

"Don't let them disturb you, my dear Muller; we will allow your
keenness all possible leeway here." The Head of Police spoke with calm
politeness, but Muller started and shivered. The emphasis on the "here"
s