Coquenil kept his appointment that night at the Three Wise Men and found Papa Tignol waiting for him, his face troubled even to the tip of his luminous purple nose. In vain the old man tried to show interest in a neighboring game of dominoes; the detective saw at a glance that his faithful friend had heard the bad news and was mourning over it.

"Ah, M. Paul," cried Tignol. "This is a pretty thing they tell me. Nom d'un chien, what a pack of fools they are!"

"Not so loud," cautioned Coquenil with a quiet smile. "It's all right, Papa Tignol, it's all for the best."

"All for the best?" stared the other. "But if you're off the force?"

"Wait a little and you'll understand," said the detective in a low tone, then as the tavern door opened: "Here is Pougeot! I telephoned him. Good evening, Lucien," and he shook hands cordially with the commissary, whose face wore a serious, inquiring look. "Will you have something, or shall we move on?" and, under his breath, he added: "Say you don't want anything."

"I don't want anything," obeyed Pougeot with a puzzled glance.

"Then come, it's a quarter past ten," and tossing some money to the waiter, Coquenil led the way out.

Drawn up in front of the tavern was a taxi-auto, the chauffeur bundled up to the ears in bushy gray furs, despite the mild night. There was a leather bag beside him.

"Is this your man?" asked Pougeot.

"Yes," said M. Paul, "get in. If you don't mind I'll lower this front window so that we can feel the air." Then, when the commissary and Tignol were seated, he gave directions to the driver. "We will drive through the bois and go out by the Porte Dauphine. Not too fast."

The man touched his cap respectfully, and a few moments later they were running smoothly to the west, over the wooden pavement of the Rue de Rivoli.

"Now we can talk," said Coquenil with an air of relief. "I suppose you both know what has happened?"

The two men replied with sympathetic nods.

"I regard you, Lucien, as my best friend, and you, Papa Tignol, are the only man on the force I believe I can absolutely trust."

Tignol bobbed his little bullet head back and forth, and pulled furiously at his absurd black mustache. This, was the greatest compliment he had ever received. The commissary laid an affectionate hand on Coquenil's arm. "You know I'll stand by you absolutely, Paul; I'll do anything that is possible. How do you feel about this thing yourself?"

"I felt badly at first," answered the other. "I was mortified and bitter. You know what I gave up to undertake this case, and you know how I have thrown myself into it. This is Wednesday night, the crime was committed last Saturday, and in these four days I haven't slept twelve hours. As to eating—well, never mind that. The point is, I was in it, heart and soul, and—now I'm out of it."

"An infernal shame!" muttered Tignol.

"Perhaps not. I've done some hard thinking since I got word this morning that my commission was canceled, and I have reached an important conclusion. In the first place, I am not sure that I haven't fallen into the old error of allowing my judgment to be too much influenced by a preconceived theory. I wouldn't admit this for the world to anyone but you two. I'd rather cut my tongue out than let Gibelin know it. Careful, there," he said sharply, as their wheels swung dangerously near a stone shelter in the Place de la Concorde.

Both Pougeot and Tignol noted with surprise the half-resigned, half-discouraged tone of the famous detective.

"You don't mean that you think the American may be guilty?" questioned the commissary.

"Never in the world!" grumbled Tignol.

"I don't say he is guilty," answered M. Paul, "but I am not so sure he is innocent. And, if there is doubt about that, then there is doubt whether this case is really a great one. I have assumed that Martinez was killed by an extraordinary criminal, for some extraordinary reason, but—I may have been mistaken."

"Of course," agreed Pougeot. "And if you were mistaken?"

"Then I've been wasting my time on a second-class investigation that a second-class man like Gibelin could have carried on as well as I; and losing the Rio Janeiro offer besides." He leaned forward suddenly toward the chauffeur. "See here, what are you trying to do?" As he spoke they barely escaped colliding with a cab coming down the Champs ElysÉes.

"It was his fault; one of his lanterns is out," declared the chauffeur, and, half turning, he exchanged curses with the departing jehu.

They had now reached Napoleon's arch, and, at greater speed, the automobile descended the Avenue de la Grande ArmÉe.

"Are you thinking of accepting the Rio Janeiro offer?" asked the commissary presently.

"Very seriously; but I don't know whether it's still open. I thought perhaps you would go to the Brazilian Embassy and ask about it delicately. I don't like to go myself, after this affair. Do you mind?"

"No, I don't mind, of course I don't mind," answered, Pougeot, "but, my dear Paul, aren't you a little on your nerves to-night; oughtn't you to think the whole matter over before deciding?"

"That's right," agreed Tignol.

"What is there to think about?" said Coquenil. "If you've got anything to say, either of you, say it now. Run on through the bois," he directed the chauffeur, "and then out on the St. Cloud road. This air is doing me a lot of good," he added, drawing in deep breaths.

For some minutes they sat silent, speeding along through the Bois de Boulogne, dimly beautiful under a crescent moon, on past crowded restaurants with red-clad musicians on the terraces, on past the silent lake and then through narrow and deserted roads until they had crossed the great park and emerged upon the high-way.

"Where are we going, anyway?" inquired Tignol.

"For a little ride, for a little change," sighed M. Paul.

"Come, come," urged Pougeot, "you are giving way too much. Now listen to me."

Then, clearly and concisely, the commissary went over the situation, considering his friend's problem from various points of view; and so absorbed was he in fairly setting forth the advantages and disadvantages of the Rio Janeiro position that he did not observe Coquenil's utter indifference to what he was saying. But Papa Tignol saw this, and gradually, as he watched the detective with his shrewd little eyes, it dawned upon the old man that they were not speeding along here in the night, a dozen miles out of Paris, simply for their health, but that something special was preparing.

"What in the mischief is Coquenil up to?" wondered Tignol.

And presently, even Pougeot, in spite of his preoccupation, began to realize that there was something peculiar about this night promenade, for as they reached a crossroad, M. Paul ordered the chauffeur to turn into it and go ahead as fast as he pleased. The chauffeur hesitated, muttered some words of protest, and then obeyed.

"We are getting right out into wild country," remarked the commissary.

"Don't you like wild country?" laughed Coquenil. "I do." It was plain that his spirits were reviving.

They ran along this rough way for several miles, and presently came to a small house standing some distance back from the road.

"Stop here!" ordered the detective. "Now," he turned to Pougeot, "I shall learn something that may fix my decision." Then, leaning forward to the chauffeur, he said impressively: "Ten francs extra if you help me now."

These words had an immediate effect upon the man, who touched his cap and asked what he was to do.

"Go to this house," pointed M. Paul, "ring the bell and ask if there is a note for M. Robert. If there is, bring the note to me; if there isn't, never mind. If anyone asks who sent you, say M. Robert himself. Understand?"

"Oui, m'sieur," replied the chauffeur, and, saluting again, he strode away toward the house.

The detective watched his receding figure as it disappeared in the shadows, then he called out: "Wait, I forgot something."

The chauffeur turned obediently and came back.

"Take a good look at him now," said Coquenil to Tignol in a low tone. Then to the man: "There's a bad piece of ground in the yard; you'd better have this," and, without warning, he flashed his electric lantern full in the chauffeur's face.

"Merci, m'sieur," said the latter stolidly after a slight start, and again he moved away, while Tignol clutched M. Paul's arm in excitement.

"You saw him?" whispered the detective.

"Did I see him!" exulted the other. "Oh, the cheek of that fellow!"

"You recognized him?"

"Did I? I'd know those little pig eyes anywhere. And that brush of a mustache! Only half of it was blacked."

"Good; that's all I want," and, stepping out of the auto, Coquenil changed quickly to the front seat. Then he drew the starting lever and the machine began to move.

"Halloa! What are you doing?" cried the chauffeur, running toward them.

"Going back to Paris!" laughed Coquenil. "Hope you find the walking good, Gibelin!"

"It's only fifteen miles," taunted Tignol.

"You loafer, you blackguard, you dirty dog!" yelled Gibelin, dancing in a rage.

"Try to be more original in your detective work," called M. Paul. "Au revoir."

They shot away rapidly, while the outraged and discomfited fat man stood in the middle of the road hurling after them torrents of blasphemous abuse that soon grew faint and died away.

"What in the world does this mean?" asked Pougeot in astonishment.

Coquenil slowed down the machine and turned. "I can't talk now; I've got to drive this thing. It's lucky I know how."

"But—just a moment. That note for M. Robert? There was no Robert?"

"Of course not."

"And—and you knew it was Gibelin all the time?"

"Yes. Be patient, Lucien, until we get back and I'll tell you everything."

The run to Paris took nearly an hour, for they made a dÉtour, and Coquenil drove cautiously; but they arrived safely, shortly after one, and left the automobile at the company's garage, with the explanation (readily accepted, since a police commissary gave it) that the man who belonged with the machine had met with an accident; indeed, this was true, for the genuine chauffeur had used Gibelin's bribe money in unwise libations and appeared the next morning with a battered head and a glib story that was never fully investigated.

"Now," said Coquenil, as they left the garage, "where can we go and be quiet? A cafÉ is out of the question—we mustn't be seen. Ah, that room you were to take," he turned to Tignol. "Did you get it?"

"I should say I did," grumbled the old man, "I've something to tell you."

"Tell me later," cut in the detective. "We'll go there. We can have something to eat sent in and—" he smiled indulgently at Tignol—"and something to drink. Hey, cocher!" he called to a passing cab, and a moment later the three men were rolling away to the Latin Quarter, with Coquenil's leather bag on the front seat.

"Enfin!" sighed Pougeot, when they were finally settled in Tignol's room, which they reached after infinite precautions, for M. Paul seemed to imagine that all Paris was in a conspiracy to follow them.

"I've been watched every minute since I started on this case," he said thoughtfully. "My house has been watched, my servant has been watched, my letters have been opened; there isn't one thing I've done that they don't know."

"They? Who?" asked the commissary.

"Ah, who?" repeated M. Paul. "If I only knew. You saw what they did with Gibelin to-night, set him after me when he is supposed to be handling this case. Fancy that! Who gave Gibelin his orders? Who had the authority? That's what I want to know. Not the chief, I swear; the chief is straight in this thing. It's some one above the chief. Lucien, I told you this was a great case and—it is."

"Then you didn't mean what you were saying in the automobile about having doubts?"

"Not a word of it."

"That was all for Gibelin?"

"Exactly. There's a chance that he may believe it, or believe some of it. He's such a conceited ass that he may think I only discovered him just at the last."

"And you're not thinking of going to Rio Janeiro?"

Coquenil shut his teeth hard, and there came into his eyes a look of indomitable purpose. "Not while the murderer of Martinez is walking about this town laughing at me. I expect to do some laughing myself before I get through with this case."

Both men stared at him. "But you are through."

"Am I? Ha! Through? I want to tell you, my friends, that I've barely begun."

"My dear Paul," reasoned the commissary, "what can you do off the force? How can you hope to succeed single-handed, when it was hard to succeed with the whole prefecture to help you?"

Coquenil paused, and then said mysteriously: "That's the point, did they help me? Or hinder me? One thing is certain: that if I work alone, I won't have to make daily reports for the guidance of some one higher up."

"You don't mean—" began the commissary with a startled look.

M. Paul nodded gravely. "I certainly do—there's no other way of explaining the facts. I was discharged for a trivial offense just as I had evidence that would prove this American innocent. They don't want him proved innocent. And they are so afraid I will discover the truth that they let the whole investigation wait while Gibelin shadows me. Well, he's off my track now, and by to-morrow they can search Paris with a fine-tooth comb and they won't find a trace of Paul Coquenil."

"You're going away?"

"No. I'm going to—to disappear," smiled the detective. "I shall work in the dark, and, when the time comes, I'll strike in the dark."

"You'll need money?"

Coquenil shook his head. "I have all the money I want, and know where to go for more. Besides, my old partner here is going to lay off for a few weeks and work with me. Eh, Papa Tignol?"

Tignol's eyes twinkled. "A few weeks or a few months is all the same to me. I'll follow you to the devil, M. Paul."

"That's right, that's where we're going. And when I need you, Lucien, you'll hear from me. I wanted you to understand the situation. I may have to call on you suddenly; you may get some strange message by some queer messenger. Look at this ring. Will you know it? A brown stone marked with Greek characters. It's debased Greek. The stone was dug up near Smyrna, where it had lain for fourteen hundred years. It's a talisman. You'll listen to anyone who brings you this ring, old friend? Eh?"

Pougeot grasped M. Paul's hand and wrung it affectionately. "And honor his request to the half of my kingdom," he laughed, but his eyes were moist. He had a vivid impression that his friend was entering on a way of great and unknown peril.

"Well," said Coquenil cheerfully, "I guess that's all for to-night. There's a couple of hours' work still for Papa Tignol and me, but it's half past two, Lucien, and, unless you think of something——"

"No, except to wish you luck," replied the commissary, and he started to go.

"Wait," put in Tignol, "there's something I think of. You forget I've been playing the flute to-day."

"Ah, yes, of course! Any news?" questioned the detective.

The old man rubbed his nose meditatively. "My news is asleep in the next room. If it wasn't so late I'd bring him in. He's a little shrimp of a photographer, but—he's seen your murderer, all right."

"The devil!" started M. Paul. "Where?"

Tignol drew back the double doors of a long window, and pointed out to a balcony running along the front of the hotel.

"There! Let me tell you first how this floor is arranged. There are six rooms opening on that balcony. See here," and taking a sheet of paper, he made a rough diagram.

"Now, then," continued Papa Tignol, surveying his handiwork with pride, "I think that is clear. B, here, is the balcony just outside, and there are the six rooms with windows opening on it. We are in this room D, and my friend, the little photographer, is in the next room E, peacefully sleeping; but he wasn't peaceful when he came home to-night and heard me playing that flute, although I played in my best manner, eh, eh! He stood it for about ten minutes, and then, eh, eh! It was another case of through the wall, first one boot, bang! then another boot, smash! only there were no holes for the boots to come through. And then it was profanity! For a small man he had a great deal of energy, eh, eh! that shrimp photographer! I called him a shrimp when he came bouncing in here."

"Well, well?" fretted Coquenil.

"Then we got acquainted. I apologized and offered him beer, which he likes; then he apologized and told me his troubles. Poor fellow, I don't wonder his nerves are unstrung! He's in love with a pretty dressmaker who lives in this room C. She is fair but fickle—he tells me she has made him unhappy by flirting with a medical student who lives in this room G. Just a minute, I'm coming to the point.

"It seems the little photographer has been getting more and more jealous lately. He was satisfied that his lady love and the medical student used this balcony as a lover's lane, and he began lying in wait at his window for the medical student to steal past toward the dress-maker's room."

"Yes?" urged the detective with growing interest.

"For several nights last week he waited and nothing happened. But he's a patient little shrimp, so he waited again Saturday night and—something did happen. Saturday night!"

"The night of the murder," reflected the commissary.

"That's it. It was a little after midnight, he says, and suddenly, as he stood waiting and listening, he heard a cautious step coming along the balcony from the direction of the medical student's room, G. Then he saw a man pass his window, and he was sure it was the medical student. He stepped out softly and followed him as far as the window of room C. Then, feeling certain his suspicions were justified, he sprang upon the man from behind, intending to chastise him, but he had caught the wrong pig by the ear, for the man turned on him like a flash and—it wasn't the medical student."

"Who was it? Go on!" exclaimed the others eagerly.

"He doesn't know who it was, or anything about the man except that his hand shut like a vise on the shrimp's throat and nearly choked the life out of him. You can see the nail marks still on the cheek and neck; but he remembers distinctly that the man carried something in his hand."

"My God! The missing pair of boots!" cried Coquenil. "Was it?"

Tignol nodded. "Sure! He was carrying 'em loose in his hand. I mean they were not wrapped up, he was going to leave 'em in Kittredge's room—here it is, A." He pointed to the diagram.

"It's true, it must be true," murmured M. Paul. "And what then?"

"Nothing. I guess the man saw it was only a shrimp he had hold of, so he shook him two or three times and dropped him back into his own room; and he never said a word."

"And the boots?"

"He must have taken the boots with him. The shrimp peeped out and saw him go back into this room F, which has been empty for several weeks. Then he heard steps on the stairs and the slam of the heavy street door. The man was gone."

Coquenil's face grew somber. "It was the assassin," he said; "there's no doubt about it."

"Mightn't it have been some one he sent?" suggested Pougeot.

"No—that would have meant trusting his secret to another man, and he hasn't trusted anyone. Besides, the fierce way he turned on the photographer shows his nervous tension. It was the murderer himself and—" The detective stopped short at the flash of a new thought. "Great heavens!" he cried, "I can prove it, I can settle the thing right now. You say his nail marks show?"

Tignol shrugged his shoulders. "They show as little scratches, but not enough for any funny business with a microscope."

"Little scratches are all I want," said the other, snapping his fingers excitedly. "It's simply a question which side of his throat bears the thumb mark. We know the murderer is a left-handed man, and, being suddenly attacked, he certainly used the full strength of his left hand in the first desperate clutch. He was facing the man as he took him by the throat, so, if he used his left hand, the thumb mark must be on the left side of the photographer's throat, whereas if a right-handed man had done it, the thumb mark would be on the right side. Stand up here and take me by the throat. That's it! Now with your left hand! Don't you see?"

"Yes," said Tignol, making the experiment, "I see."

"Now bring the man in here, wake him, tell him—tell him anything you like. I must know this."

"I'll get him in," said the commissary. "Come," and he followed Tignol into the hall.

A few moments later they returned with a thin, sleepy little person wrapped in a red dressing gown. It was the shrimp.

"There!" exclaimed Papa Tignol with a gesture of satisfaction.

The photographer, under the spell of Pougeot's authority, stood meekly for inspection, while Coquenil, holding a candle close, studied the marks on his face. There, plainly marked on the left side of the throat was a single imprint, the curving red mark where a thumb nail had closed hard against the jugular vein (this man knew the deadly pressure points), while on the right side of the photographer's face were prints of the fingers.

"He used his left hand, all right," said Coquenil, "and, sapristi, he had sharp nails!"

"Parbleu!" mumbled the shrimp.

"Here over the cheek bone is the mark of his first finger. And here, in front of the ear, is his second finger, and here is his third finger, just behind the ear, and here, way down on the neck, is his little finger. Lord of heaven, what a reach! Let's see if I can put my fingers on these marks. There's the thumb, there's the first finger—stand still, I won't hurt you! There's the second finger, and the third, and—look at that, see that mark of the little finger nail. I've got long fingers myself, but I can't come within an inch of it. You try."

"'Stand still, I won't hurt you.'"

Patiently the photographer stood still while the commissary and Tignol tried to stretch their fingers over the red marks that scarred his countenance. And neither of them succeeded. They could cover all the marks except that of the little finger, which was quite beyond their reach.

"He has a very long little finger," remarked the commissary, and, in an instant, Coquenil remembered Alice's words that day as she looked at his plaster casts.

A very long little finger! Here it was! One that must equal the length of that famous seventeenth-century criminal's little finger in his collection. But this man was living! He had brought back Kittredge's boots! He was left-handed! He had a very long little finger! And Alice knew such a man!