Lupin was silent, impressed, in spite of himself, by the man's anguish. He sat long thinking and then rose and said to the head-waiter:
"Here, here's your money; but, if you want to live in peace, you will do well not to breathe a word of our conversation to anybody."
He left the restaurant with Doudeville and walked to the Porte Saint-Denis without speaking, absorbed in all that he had heard. At last, he seized his companion's arm and said:
"Listen to me, Doudeville, carefully. Go to the Gare du Nord. You will get there in time to catch the Luxemburg express. Go to Veldenz, the capital of the grand-duchy of Zweibrucken-Veldenz. At the town-hall, you will easily obtain the birth-certificate of the Chevalier de Malreich and further information about the family. You will be back on the day after to-morrow: that will be Saturday."
"Am I to let them know at the detective-office?"
"I'll see to that. I shall telephone that you are ill. Oh, one word more: on Saturday, meet me at twelve o'clock in a little café on the Route de la Revolte, called the Restaurant Buffalo. Come dressed as a workman."
The next day, Lupin, wearing a short smock and a cap, went down to Neuilly and began his investigations at No. 3, Route de la Revolte. A gateway opened into an outer yard; and here he found a huge block of workmen's dwellings, a whole series of passages and workshops, with a swarming population of artisans, women and brats. In a few minutes, he had won the good-will of the portress, with whom he chatted for an hour on the most varied topics. During this hour, he saw three men pass, one after the other, whose manner struck him:
"That's game," he thought, "and gamy game at that! . . . They follow one another by scent! . . . Look quite respectable, of course, but with the eye of the hunted deer which knows that the enemy is all around and that every tuft, every blade of grass may conceal an ambush."
That afternoon and on the Saturday morning, he pursued his inquiries and made certain that Altenheim's seven accomplices all lived on the premises. Four of them openly followed the trade of second-hand clothes-dealers. Two of the others sold newspapers; and the third described himself as a broker and was nicknamed accordingly.