“Yesterday evening.  I see.  And where is the paper from?”

“Upon my word, Monsieur, I can’t say.  I wanted something to wind my string on.  I picked this bit up behind the coach-house where they fling all the rubbish of the house to be taken into the street at night.”

Don Luis pursued his investigations.  He questioned or asked Mlle. Levasseur to question the other servants.  He discovered nothing; but one fact remained:  the article in the Echo de France had been written, as the rough draft which he had picked up proved, by somebody who lived in the house or who was in touch with one of the people in the house.

The enemy was inside the fortress.

But what enemy?  And what did he want?  Merely Perenna’s arrest?

All the remainder of the afternoon Don Luis continued anxious, annoyed by the mystery that surrounded him, incensed at his own inaction, and especially at that threatened arrest, which certainly caused him no uneasiness, but which hampered his movements.

Accordingly, when he was told at about ten o’clock that a man who gave the name of Alexandre insisted on seeing him, he had the man shown in; and when he found himself face to face with Mazeroux, but Mazeroux disguised beyond recognition and huddled in an old cloak, he flung himself on him as on a prey, hustling and shaking him.

“So it’s you, at last?” he cried.  “Well, what did I tell you?  You can’t make head or tail of things at the police office and you’ve come for me!  Confess it, you numskull!  You’ve come to fetch me!  Oh, how funny it all is!  Gad, I knew that you would never have the cheek to arrest me, and that the Prefect of Police would manage to calm the untimely ardour of that confounded Weber!  To begin with, one doesn’t arrest a man whom one has need of.  Come, out with it!  Lord, how stupid you look!  Why don’t you answer?  How far have you got at the office?  Quick, speak!  I’ll settle the thing in five seconds.  Just tell me about your inquiry in two words, and I’ll finish it for you in the twinkling of a bed-post, in two minutes by my watch.  Well, you were saying—­”

“But, Chief,” spluttered Mazeroux, utterly nonplussed.

“What!  Must I drag the words out of you?  Come on!  I’ll make a start.  It has to do with the man with the ebony walking-stick, hasn’t it?  The one we saw at the Cafe du Pont-Neuf on the day when Inspector Verot was murdered?”

“Yes, it has.”

“Have you found his traces?”

“Yes.”

“Well, come along, find your tongue!”

“It’s like this, Chief.  Some one else noticed him besides the waiter.  There was another customer in the cafe; and this other customer, whom I ended by discovering, went out at the same time as our man and heard him ask somebody in the street which was the nearest underground station for Neuilly.”

“Capital, that.  And, in Neuilly, by asking questions on every side, you ferreted him out?”