And, suddenly, Lupin remembered: two years ago, Prasville and Daubrecq the deputy had had a personal encounter on the Place du Palais-Bourbon. The incident made a great stir at the time. No one knew the cause of it. Prasville had sent his seconds to Daubrecq on the same day; but Daubrecq refused to fight.

A little while later, Prasville was appointed secretary-general.

"Very odd, very odd," said Lupin, who remained plunged in thought, while continuing to observe Prasvile's movements.

At seven o'clock Prasville's group of men moved away a few yards, in the direction of the Avenue Henri-Martin. The door of a small garden on the right of the house opened and Daubrecq appeared. The two detectives followed close behind him and, when he took the Rue-Taitbout train, jumped on after him.

Prasville at once walked across the square and rang the bell. The garden-gate was between the house and the porter's lodge. The portress came and opened it. There was a brief conversation, after which Prasville and his companions were admitted.

"A domiciliary visit," said Lupin. "Secret and illegal. By the strict rules of politeness, I ought to be invited. My presence is indispensable."

Without the least hesitation he went up to the house, the door of which had not been closed, and, passing in front of the portress, who was casting her eyes outside, he asked, in the hurried tones of a person who is late for an appointment:

"Have the gentlemen come?"

"Yes, you will find them in the study."

His plan was quite simple: if any one met him, he would pretend to be a tradesman. But there was no need for this subterfuge. He was able, after crossing an empty hail, to enter a dining-room which also had no one in it, but which, through the panes of a glass partition that separated the dining-room from the study, afforded him a view of Prasville and his five companions.

Prasville opened all the drawers with the aid of false keys. Next, he examined all the papers, while his companions took down the books from the shelves, shook the pages of each separately and felt inside the bindings.

"Of course, it's a paper they're looking for," said Lupin. "Bank-notes, perhaps... "

Prasville exclaimed:

"Whatrot! We shan't find a thing!"

Yet he obviously did not abandon all hope of discovering what he wanted, for he suddenly seized the four bottles in a liqueur-stand, took out the four stoppers and inspected them.

"Hullo!" thought Lupin. "Now he's going for decanter-stoppers! Then it's not a question of a paper? Well, I give it up."

Prasville next lifted and examined different objects; and he asked:

"How often have you been here?"

"Six times last winter," was the reply.

"And you have searched the house thoroughly?"

"Every one of the rooms, for days at a time, while he was visiting his constituency."

"Still... still ... ." And he added, "Has he no servant at present?"

"No, he is looking for one. He has his meals out and the portress keeps the house as best she can. The woman is devoted to us... "