"But the body?"

"The body has not been found, but there is nothing excessively surprising in that. As a matter of fact, the trail which I followed brought me to the church at Varengeville and the old cemetery perched on the top of the cliff. From there it is a sheer precipice, a fall of over three hundred feet to the rocks and the sea below. In a day or two, a stronger tide than usual will cast up the body on the beach."

"Obviously. This is all very simple."

"Yes, it is all very simple and doesn't trouble me in the least. Lupin is dead, his accomplices heard of it and, to revenge themselves, have killed Mlle. de Saint-Veran. These are facts which did not even require checking. But Lupin?"

"What about him?"

"What has become of him? In all probability, his confederates removed his corpse at the same time that they carried away the girl; but what proof have we? None at all. Any more than of his staying in the ruins, or of his death, or of his life. And that is the real mystery, M. Beautrelet. The murder of Mlle. Raymonde solves nothing. On the contrary, it only complicates matters. What has been happening during the past two months at the Chateau d'Ambrumesy? If we don't clear up the riddle, young man, others will give us the go-by."

"On what day are those others coming?"

"Wednesday-Tuesday perhaps-"

Beautrelet seemed to be making an inward calculation and then declared:

"Monsieur le Juge d'Instruction, this is Sat.u.r.day. I have to be back at school on Monday evening. Well, if you will have the goodness to be here at ten o'clock exactly on Monday morning, I will try to give you the key to the riddle."

"Really, M. Beautrelet-do you think so? Are you sure?"

"I hope so, at any rate."

"And where are you going now?"

"I am going to see if the facts consent to fit in with the general theory which I am beginning to perceive."

"And if they don't fit in?"

"Well, Monsieur le Juge d'Instruction," said Beautrelet, with a laugh, "then it will be their fault and I must look for others which, will prove more tractable. Till Monday, then?"

"Till Monday."

A few minutes later, M. Filleul was driving toward Dieppe, while Isidore mounted a bicycle which he had borrowed from the Comte de Gesvres and rode off along the road to Yerville and Caudebec-en-Caux.

There was one point in particular on which the young man was anxious to form a clear opinion, because this just appeared to him to be the enemy's weakest point. Objects of the size of the four Rubens pictures cannot be juggled away. They were bound to be somewhere. Granting that it was impossible to find them for the moment, might one not discover the road by which they had disappeared?

What Beautrelet surmised was that the four pictures had undoubtedly been carried off in the motor car, but that, before reaching Caudebec, they were transferred to another car, which had crossed the Seine either above Caudebec or below it. Now the first horse-boat down the stream was at Quillebeuf, a greatly frequented ferry and, consequently, dangerous. Up stream, there was the ferry-boat at La Mailleraie, a large, but lonely market-town, lying well off the main road.

By midnight, Isidore had covered the thirty-five or forty miles to La Mailleraie and was knocking at the door of an inn by the waterside. He slept there and, in the morning, questioned the ferrymen.

They consulted the counterfoils in the traffic-book. No motor-car had crossed on Thursday the 23rd of April.

"A horse-drawn vehicle, then?" suggested Beautrelet. "A cart? A van?"

"No, not either."

Isidore continued his inquiries all through the morning. He was on the point of leaving for Quillebeuf, when the waiter of the inn at which he had spent the night said:

"I came back from my thirteen days' training on the morning of which you are speaking and I saw a cart, but it did not go across."

"Really?"

"No, they unloaded it onto a flat boat, a barge of sorts, which was moored to the wharf."

"And where did the cart come from?"

"Oh, I knew it at once. It belonged to Master Vatinel, the carter."

"And where does he live?"

"At Louvetot."

Beautrelet consulted his military map. The hamlet of Louvetot lay where the highroad between Yvetot and Caudebec was crossed by a little winding road that ran through the woods to La Mailleraie.

Not until six o'clock in the evening did Isidore succeed in discovering Master Vatinel, in a pothouse. Master Vatinel was one of those artful old Normans who are always on their guard, who distrust strangers, but who are unable to resist the lure of a gold coin or the influence of a gla.s.s or two:

"Well, yes, sir, the men in the motor car that morning had told me to meet them at five o'clock at the crossroads. They gave me four great, big things, as high as that. One of them went with me and we carted the things to the barge."

"You speak of them as if you knew them before."

"I should think I did know them! It was the sixth time they were employing me."

Isidore gave a start:

"The sixth time, you say? And since when?"

"Why every day before that one, to be sure! But it was other things then-great blocks of stone-or else smaller, longish ones, wrapped up in newspapers, which they carried as if they were worth I don't know what. Oh, I mustn't touch those on any account!-But what's the matter? You've turned quite white."

"Nothing-the heat of the room-"

Beautrelet staggered out into the air. The joy, the surprise of the discovery made him feel giddy. He went back very quietly to Varengeville, slept in the village, spent an hour at the mayor's offices with the school-master and returned to the chateau. There he found a letter awaiting him "care of M. le Comte de Gesvres." It consisted of a single line:

"Second warning. Hold your tongue. If not-"

"Come," he muttered. "I shall have to make up my mind and take a few precautions for my personal safety. If not, as they say-"

It was nine o'clock. He strolled about among the ruins and then lay down near the cloisters and closed his eyes.

"Well, young man, are you satisfied with the results of your campaign?"

It was M. Filleul.

"Delighted, Monsieur le Juge d'Instruction."

"By which you mean to say-?"

"By which I mean to say that I am prepared to keep my promise-in spite of this very uninviting letter."