“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.”