"Where does this ball of string come from?"

"The string, sir? Why, from the harness-room, I think. It must have been that little she-devil of a Mirza who--"

"And when did you wind the string round the paper?"

"Yesterday evening, Monsieur."

"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.

Leva.s.seur 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?"

"And even learnt his name, Chief: Hubert Lautier, of the Avenue du Roule.

Only he decamped from there six months ago, leaving his furniture behind him and taking nothing but two trunks."

"What about the post-office?"

"We have been to the post-office. One of the clerks recognized the description which we supplied. Our man calls once every eight or ten days to fetch his mail, which never amounts to much: just one or two letters.

He has not been there for some time."

"Is the correspondence in his name?"

"No, initials."

"Were they able to remember them?"

"Yes: B.R.W.8."

"Is that all?"

"That is absolutely all that I have discovered. But one of my fellow officers succeeded in proving, from the evidence of two detectives, that a man carrying a silver-handled ebony walking-stick and a pair of tortoise-sh.e.l.l gla.s.ses walked out of the Gare d'Auteuil on the evening of the double murder and went toward Renelagh. Remember the presence of Mme.

Fauville in that neighbourhood at the same hour. And remember that the crime was committed round about midnight. I conclude from this--"

"That will do; be off!"

"But--"

"Get!"

"Then I don't see you again?"

"Meet me in half an hour outside our man's place."

"What man?"

"Marie Fauville's accomplice."

"But you don't know--"

"The address? Why, you gave it to me yourself: Boulevard Richard-Wallace, No. 8. Go! And don't look such a fool."

He made him spin round on his heels, took him by the shoulders, pushed him to the door, and handed him over, quite flabbergasted, to a footman.

He himself went out a few minutes later, dragging in his wake the detectives attached to his person, left them posted on sentry duty outside a block of flats with a double entrance, and took a motor cab to Neuilly.

He went along the Avenue de Madrid on foot and turned down the Boulevard Richard-Wallace, opposite the Bois de Boulogne. Mazeroux was waiting for him in front of a small three-storied house standing at the back of a courtyard contained within the very high walls of the adjoining property.

"Is this number eight?"

"Yes, Chief, but tell me how--"

"One moment, old chap; give me time to recover my breath."

He gave two or three great gasps.

"Lord, how good it is to be up and doing!" he said. "Upon my word, I was getting rusty. And what a pleasure to pursue those scoundrels! So you want me to tell you?"

He pa.s.sed his arm through the sergeant's.