At last, however, the coquettish landlady made her appearance as radiant as a spring morning.  She probably wished to make up for the time she had spent over her toilet, for as she turned the corner she began to run.  Lecoq waited till she was out of sight, and then bounding from his place of concealment, he burst into the Hotel de Mariembourg like a bombshell.

Fritz, the Bavarian lad, must have been warned that the house was to be left in his sole charge for some hours; for having comfortably installed himself in his mistress’s own particular armchair, with his legs resting on another one, he had already commenced to fall asleep.

“Wake up!” shouted Lecoq; “wake up!”

At the sound of this voice, which rang like a trumpet blast, Fritz sprang to his feet, frightened half out of his wits.

“You see that I am an agent of the Prefecture of Police,” said the visitor, showing his card.  “Now, if you wish to avoid all sorts of disagreeable things, the least of which will be a sojourn in prison, you must obey me.”

The boy trembled in every limb.  “Yes, mein Herr—­Monsieur, I mean—­I will obey you,” he stammered.  “But what am I to do?”

“Oh, very little.  A man is coming here in a moment:  you will know him by his black clothes and his long beard.  You must answer him word for word as I tell you.  And remember, if you make any mistake, you will suffer for it.”

“You may rely upon me, sir,” replied Fritz.  “I have an excellent memory.”

The prospect of imprisonment had terrified him into abject submission.  He spoke the truth; he would have been willing to say or do anything just then.  Lecoq profited by this disposition; and then clearly and concisely gave the lad his instructions.  “And now,” added he, “I must see and hear you.  Where can I hide myself?”

Fritz pointed to a glass door.  “In the dark room there, sir.  By leaving the door ajar you can hear and you can see everything through the glass.”

Without another word Lecoq darted into the room in question.  Not a moment too soon, however, for the bell of the outer door announced the arrival of a visitor.  It was May.  “I wish to speak to the landlady,” he said.

“What landlady?” replied the lad.

“The person who received me when I came here six weeks ago—­”

“Oh, I understand,” interrupted Fritz; “it’s Madame Milner you want to see; but you have come too late; she sold the house about a month ago, and has gone back to Alsace.”

May stamped his foot and uttered a terrible oath.  “I have come to claim something from her,” he insisted.

“Do you want me to call her successor?”

Concealed behind the glass door, Lecoq could not help admiring Fritz, who was uttering these glaring falsehoods with that air of perfect candor which gives the Germans such a vast advantage over the Latin races, who seem to be lying even when they are telling the truth.