When Richard Duvall and his companion entered the house of the French Ambassador in London, it was evident that their arrival was expected. The detective had no more than given his name to the butler who threw open the door, when the latter, with a bow of recognition, conducted them to a small reception-room to the right of the entrance, and informed them that Monsieur de Grissac would see them at once.

They did not have long to wait. The Ambassador, a thin, spare, nervous-looking man of sixty, with white hair and a gray-white mustache, came hurriedly into the room after but a few moments had elapsed, and greeting them excitedly, bade them be seated. He himself remained standing, his back to the fireplace, twirling his eyeglasses at the end of their black silk ribbon, and observing his visitors keenly.

"Monsieur Lefevre had informed me of your coming, gentlemen," he presently burst out. "We have no time to lose."

"Let us have the details of the affair, monsieur," Duvall remarked, seating himself comfortably in his chair. "So far we are completely in the dark."

"You know, do you not, that a valuable article, a small snuff box, to be exact—has been stolen from me?"

"Yes. Of that I have been informed," the detective remarked, dryly. "I am curious to learn why the loss of an article of so trivial a nature should be regarded with such seriousness."

The Ambassador's eyes snapped—he seemed almost to resent the detective's attitude. "It should be sufficient, monsieur, I think, that it is so regarded. The task before us is to recover it—not discuss the reasons for doing so."

"I disagree with you, monsieur. If the real value of the stolen article is kept from me, how can I draw any conclusions as to the probable object of its theft? Was it intrinsically valuable? Did it contain anything of value? In short, why should any one have taken the trouble to steal it? Tell me that, and I can act intelligently. Otherwise, I shall be only groping about in the dark."

"I do not think so, monsieur." The Ambassador bent upon Duvall a searching glance. "The fact that the box is gone should be sufficient. All that I ask is that you recover it. You must trace its disappearance from the material facts of the case. Conjecture will avail us nothing."

"Is the box then of no value?"

"I have not said so. As a matter of fact, its value is great. It has been an heirloom in my family for many years. At one time it belonged to Cardinal Mazarin."

"You think, then, that its intrinsic value alone might have prompted the theft?"

"I think so—indeed, I very greatly hope so."

"Why?"

The Ambassador recovered himself with a start. Evidently he had said more than he intended. It was some time before he answered the question and then he did so lamely. "Its theft by someone interested in its value as a curiosity would enable me to recover it most readily—by the payment, of course, of a sum of money."

"True. But I assume, from what you say, that there might be other reasons; that it might have been taken by those who suspected that it had another value?"

For a moment Monsieur de Grissac appeared confused. Then he waved his hand impatiently. "There are those," he said, "who seek to injure me. They know that I prized this thing highly. Their motive may have been—not money, but revenge. In that case, its recovery will be vastly more difficult."

Duvall saw that Monsieur de Grissac was not being frank with him, and for a moment he was conscious of a deep sense of annoyance. Monsieur Lefevre had, heretofore, invariably taken him into his confidence. He controlled his feelings, however, and appeared to be satisfied with the Ambassador's explanations. "What did the box contain, Monsieur de Grissac," he asked, pleasantly.

"A quantity of snuff, monsieur."

"Nothing else?"

"Nothing."

"Oh! And you, monsieur, are in the habit of using snuff?"

"Yes. It is the only form in which I use tobacco. Old-fashioned, perhaps, but I belong to the older generation." He straightened himself up suddenly. "Let us proceed, gentlemen. I fear we are wasting valuable time."

Duvall nodded. "Permit me to ask you a few more questions."

"I am at your service, monsieur."

"When did you last see the box?"

"This morning, at nine o'clock. I always carry it in the right-hand pocket of my waistcoat. To insure its safety, I had it attached to a long gold chain, which was securely fastened to the inside of the pocket. I rose this morning somewhat late, having attended a banquet last night. After having my coffee and rolls in my bedroom, I went to my dressing-room to be shaved. As I did so, I paused for a moment, drew the snuff box from the pocket of my white evening waistcoat, which my valet had hung in a closet the night before, and took a pinch of snuff from it. I then replaced it in the pocket and entered the dressing-room adjoining, where NoËl, my man, was waiting for me. He proceeded to shave me as usual, and I began to dress. Upon going to the closet in my bedroom to remove the box, and fasten it by means of the chain to the clasp in the pocket of the waistcoat I had just put on, I was amazed to find it gone. I at once summoned NoËl—"

"Summoned him?" interrupted the detective. "Was he not with you in the room?"

"No. A few moments before—as soon, in fact, as I had completed dressing, he left the apartment to give some instructions to my chauffeur."

"What did you do then?"

"I at once rushed out into the hall, calling for NoËl."

"You believed, then, that he had taken the box?"

"I could believe nothing else. No one but he had been in my rooms."

"Oh! I see. And you questioned him?"

"Yes. On reaching the hall I met one of the maids ascending the stairway. I called to her, asking if she had seen NoËl. She had not. She had been in the servants' hall—talking with the chauffeur—NoËl had not been there."

"What did you do then?"

"I rushed to his room, which is on the floor above, thinking that, if he had taken the box, and proposed to deny the fact, he would have gone there to secrete it."

"Would he not have been more likely to leave the house immediately since he knew you would discover your loss at once?"

"No. He would realize that to flee would be to admit his guilt. He could not have gone more than a few hundred feet. Capture would have been inevitable."

"Did you find the man in the room?"

"He was just leaving it as I came up."

"What did you do then?"

"I ordered him back into the room, and questioned him sharply. He denied all knowledge of the matter, and appeared to be deeply hurt at my suspicions."

"Did you believe him?"

"I do not know. The matter is incomprehensible. NoËl has been in my service for eight years. I supposed him absolutely incorruptible—absolutely honest. He also insists that after I left the bedroom, and came into the dressing-room to be shaved, he did not leave me, nor again enter the bedroom; in which case, he could not have committed the theft."

"Is this true?"

"So far as I can remember, it is." He spoke in a slightly hesitating way, and Duvall at once noticed it. "You are, then, not absolutely sure?" he asked.

"I feel confident that NoËl did not leave me, nor enter the bedroom. If I hesitated for a moment, it arose from the fact that on one or two occasions I have fallen asleep while being shaved, but this morning I am quite sure that I did not do so."

"Yet you were up late last night, and awoke feeling sleepy and tired."

"Yes." The Ambassador nodded. "That is true."

"Is there any other door to the bedroom?"

"None, except that which opens into my bath. The bathroom has no windows. It is an inside room."

"And the bedroom?"

"It has two windows, facing upon the adjoining property. There is quite thirty feet of space between the two buildings and the windows are at least twenty-five feet from the ground."

"What room is above?"

"A guest's chamber, unused and locked."

Duvall rose and began to stride up and down the room, chewing viciously upon his unlighted cigar. "After you finished questioning the man, what did you do then?"

"I searched his room thoroughly, and made him turn out the contents of his pockets, his trunk and bureau drawers."

"And you found—?"

"Nothing. That was before noon to-day. Since then, I have kept the man locked in his room, awaiting your coming. One of the other servants has remained on guard outside his door ever since."

"You did not, then, notify the police?"

"No. The matter is one that, for reasons of my own, I do not wish to become public."

"Has anything been heard from your prisoner since this morning?"

"Yes. He asked for pen and ink about one o'clock this afternoon. I went up to see him, to find out why he wanted them. He seemed deeply affected, was almost in tears, and apparently afraid to meet my gaze. He said he wished to write a note, breaking an engagement he had had for this afternoon. He usually had Wednesday afternoons off. I permitted him to write the letter."

Duvall began to show signs of deep interest on hearing this. "Where is it?" he exclaimed.

"What, monsieur?" The Ambassador evidently did not follow him.

"The letter."

"I sent it, of course."

"But you read it first?"

"Yes. It was addressed to a man named Seltz, Oscar Seltz, if I recollect correctly, at a barber shop in Piccadilly Circus, which, as you know, is close by. This fellow Seltz was a friend of NoËl's. I have several times heard him speak of him. They were accustomed to spend their afternoons off together, I understand."

"And the note?" asked Duvall, impatiently. "What did it say?"

"Merely that NoËl was unable to keep his appointment for that afternoon, and did not expect to see his friend again before his departure. Seltz must have been planning some trip. The letter, as I remember, was quite cool, almost unfriendly in its tone."

Duvall glanced at his watch. "This was about one o'clock you say?"

"Yes. The matter has no significance. We are wasting our time discussing it."

"On the contrary, monsieur, I fear it may have had the greatest significance. That letter should never have been delivered. Even now, it may be too late to prevent the consequences. Be so good, monsieur, as to conduct me to this man NoËl's room at once." He turned to Dufrenne. "You will accompany us, of course, Monsieur Dufrenne," he said, then followed the Ambassador toward the hall.

In a few moments they reached the third floor of the house, and passed along a short hall which gave entrance to a rear extension of the building, in which the servants' quarters were located. At the entrance of the hall, a maid was seated upon a stool, reading a book. She rose as the others approached, and stood respectfully aside.

"Has anything been heard from NoËl?" the Ambassador asked. "Has he asked for anything?"

"Nothing, monsieur. He has been quiet ever since six o'clock, when I took him his supper."

"What was he doing when you entered?"

"Writing, monsieur. He was sitting at the table, with a pen in his hand, and he looked up and told me to put the tray on the trunk. 'I shall ask you to take this letter to Monsieur de Grissac as soon as I have finished it,' he said. Since then I have heard nothing from him."

Duvall had preceded the Ambassador and Dufrenne to the door at the end of the short hall, and stood listening intently. In a moment, De Grissac came up, and, unlocking the door, threw it open. The room was dimly illuminated by a single candle, which smoked and guttered in its socket, apparently nearly burned out. Nothing was at first to be seen of the valet. Duvall stepped forward, then turned quickly and spoke. "Shut the door, please," he said in a tense voice.

Dufrenne did so, while the Ambassador strode forward and followed Duvall's gaze with a look of horror. On the floor beside the bed, and to the far side of the room from the door, lay the body of the unfortunate valet, his face, ghastly pale, turned toward the ceiling. But it was neither the sight of the man lying there, apparently dead, nor the agonized expression of his face, which caused both the Ambassador and Duvall to start back with exclamations of surprise. Across the man's lips was a great, dull-red blotch, which at first appeared to be a clot of blood, but which seemed, from its circular form and regular contour, more like a huge seal. And seal it was. Duvall, dropping on one knee beside the body, felt for the man's heart, at the same time looking closely at the mark upon his lips. He was quite dead, and had apparently been so for an hour or two. The blot upon his face was a great lump of red sealing wax, tightly binding together his lips, and upon it was the coarse imprint of a man's forefingers.

The Ambassador shrank back with a cry, as his eyes fell upon the ghastly sight. Dufrenne gazed at the dead man impassively. Duvall, springing to his feet, went at once to the window at the rear of the room, which stood partly open, and raising it to its full extent, looked out. The others heard him give utterance to a low whistle, as he drew back into the room.

"No one could have entered the room," cried the Ambassador, in a frightened voice. "It is thirty-five feet or more to the ground."

Duvall motioned to the window. "Look out, monsieur," he remarked, quietly.

De Grissac did so, then uttered a sudden cry. From the window to the garden below stretched a long slender wooden ladder. "It belongs to the men who have been repairing the rain spouting," he exclaimed. "They leave it in the garden, at night. I knew there was no way in which NoËl could get out."

"But clearly a way, monsieur, by which others could get in," said Duvall, quietly, as he began a minute examination of the room.

"But the snuff box—do you think it has been taken away?"

"Undoubtedly, monsieur. I suspected as much, when you showed me the man's letter. Your servant, I have no doubt, took the box while shaving you this morning. You doubtless dozed off, thus giving him the opportunity. He did not know that you had taken snuff from the box this morning shortly after arising, and imagined, no doubt, that you would suppose you had lost it some time the night before. This would relieve him of any suspicion. He hurried off to his room to secrete the box, meaning to deliver it to this friend of his, Oscar Seltz, during the afternoon. His arraignment by you, his subsequent imprisonment, no doubt frightened him and filled him with remorse—hence his rather unfriendly letter to Seltz. He had repented of his bargain, and was doubtless engaged in preparing a confession, telling you of his crime, and the reasons therefor, when the murderer entered the room.

"The latter, who probably was this man Seltz, must have become alarmed by the tone of NoËl's letter. He was, it seems clear, planning some trip away from London, upon which he was about to leave. He meant to take the snuff box with him. Upon receiving NoËl's letter he determined to see him and demand the box, if he found the latter had secured it. No doubt he made inquiries from some of the servants, on calling to see NoËl, and was informed that he was confined to his room. He then pretended to leave, but in reality, ascended to the room by means of the ladder he found in the garden, while the servants were at dinner. It was a desperate chance, but he took it. Upon arriving in the room, he found NoËl engaged in preparing his confession, insisted upon reading it, then realizing that his confederate was about to play him false, killed him, after gaining possession of the box, and departed."

The Ambassador uttered a groan. "My God," he moaned, "I am lost!"

Dufrenne, who meanwhile had been making a careful examination of the dead valet's body, rose with a mystified expression upon his face. "There are no wounds upon the body at all, Monsieur Duvall," he said. "How can you account for this man's death?"

Duvall stooped, and repeated the examination which his companion had just made. "You are right," he said. "The case is a most mysterious one."

"At least we can identify the murderer by the finger print upon the seal," De Grissac remarked, eagerly.

"I'm afraid not. This man Seltz cannot be quite a fool. Look!" He held up the forefinger of the dead man's right hand, upon which was a dull red burn, with bits of the red sealing wax about the nail. "He wasn't taking any chances." He let the already stiffening arm fall, and continued his examination of the body. "The method by which the man was killed," he remarked slowly, "is not yet clear to me. Certain finger prints on the throat indicate that he might have been strangled, but they are hardly deep or extensive enough for that. I fancy they would have resulted in temporary unconsciousness only. No—there is another reason—although what it is—" He paused as his eyes lit upon a thin shining object on the floor beside the table. "Oh, this may tell us something." He picked up the thing, which the others saw at once to be a large scarf pin, and examined it carefully.

"Did this belong to your servant, Monsieur de Grissac," he asked, holding the pin up to the light.

"Yes." The Ambassador glanced at the pin carelessly. "It was one of my own that I had given him, some months ago."

Duvall laid the scarf pin carefully upon the table, then went to the body on the floor, turned it over and made a careful examination of the back of the neck. He held the candle close, pushing aside the man's thin sandy hair. Presently he rose and placed the candle on the table beside the pin. "This was what your servant was killed with, Monsieur de Grissac," he said, as he indicated the scarf pin with his finger. "It was thrust violently into the spine, at the base of the brain. Only a tiny blood spot remains to tell the tale. This fellow Seltz is a shrewd customer."

"We do not even know that it was he who committed the crime. There is no real evidence against anyone. The snuff box may still be here. I insist that you make a thorough search."

"It would be useless, monsieur," Duvall remarked with a faint smile. "The box must have been on the table when the murderer entered the room."

"Why?"

"Because otherwise he would have searched for it, and you would have found everything in disorder. Believe me, monsieur, your servant had repented of his theft, and was about to return the box to you—it was that which caused his death. The seal upon his lips is a gruesome joke—silence—his lips are sealed—he can tell nothing."

"Seltz must be arrested at once," the Ambassador cried, in a rage.

"So far, monsieur, there is not the slightest evidence against him. Further, it is my opinion that he will leave London at once. Tell me the name of the shop in Piccadilly Circus where he was employed, and we will lose no further time in getting on his trail."

The Ambassador was not entirely certain of the location of the shop. He had never visited it. The name, he remembered, was given in the note as Perrier. The note had been delivered by one of the servants; he could tell where, and to whom he had delivered it.

Duvall recommended to the Ambassador that he report the murder to the police at once, but requested that no mention be made of the presence of himself and Monsieur Dufrenne. "We should be held as witnesses," he cautioned Monsieur de Grissac, "and that would seriously interfere with our plans. Let us interview the servant who took the letter at once."

The latter, a groom, was soon disposed of. He gave the number and location of the barber shop in Piccadilly Circus, a short distance away, and reported that he had handed the message to a dark, smooth-shaven man at the second chair. He did not know Seltz, but the proprietor had pointed him out in response to his inquiries. His description of the man was vague and unsatisfactory; he was unable to give any further information on the subject. Investigations as to anyone having made inquiries at the servants' entrance during the evening, regarding NoËl, elicited the information that a heavily built, dark man, smooth-shaven, had called about half-past seven, and upon being informed that the valet was confined to his room and could not be seen, had disappeared. No one had taken any particular notice of his coming or going.

When the party had once more assembled in the reception-room, Duvall turned to Monsieur de Grissac. "There is nothing more to be accomplished here, monsieur," he remarked, quietly. "We will get after this fellow Seltz at once, and I trust that before long the missing snuff box will be returned to you."

The Ambassador shook hands with his guests, in a state of extreme agitation. "Lose no time," he urged. "You must recover the box before the thief has an opportunity to turn it over to those who are back of him, else it will be too late. I shall pray for your success." He stood at the door as his guests departed, shaking as though with a palsy. "It is a matter of greater moment than life itself. I trust you will not fail."