Stapleton's chauffeur, while in the rear sat a figure, in dark suit and Panama hat, which seemed for all the world like that of the banker himself. Had a casual observer not seen Mr. Stapleton turn back toward Paris, he would have concluded that he was still on his way toward Versailles.

The occupants of this second car also appeared to be keenly watching the various automobiles which pa.s.sed them, as though expecting some signal, some recognition; yet, in spite of their eager and expectant glances, they seemed doomed to disappointment.

At last Versailles was reached. The elderly man in the tonneau gave a short command, his chauffeur turned the car about, and they began to return to Paris. Nothing further whatever happened on the Versailles road.

Meanwhile, Richard Duvall, at the Porte de Versailles, was carefully scrutinizing the various incoming machines that pa.s.sed the gate and entered the city. With a brilliant electric searchlight he examined their bodies and wheels, looking always for the telltale red stains which would identify the kidnappers' car. Beside him stood Vernet, one of the Prefect's a.s.sistants, with whom Duvall had become well acquainted during his former stay in Paris.

"Well, Monsieur Duvall," remarked the latter, "a most ingenious plan--this of yours. I wonder if it will be successful?"

"I feel sure of it."

"I hope you are right." He looked at his watch. "Half past eight. About time, I should think, from what you tell me. Here is a big fellow, now.

A Pasquet, by her looks. Six-cylinder, too."

Duvall glanced at the oncoming car. A wagon which preceded it was just pa.s.sing the gates. The big Pasquet slowed up, and almost stopped.

The detective threw the rays of his searchlight on the body of the car, then started back with an exclamation. From one end to the other, the dark green finish of the sides and wheels was spattered and streaked with bright red paint. Dust had settled in it, in places, especially on the wheels; but above, on the doors, it was clear and unmistakable.

"Vernet," he shouted, excitedly, "it is the one! Quick! Don't let them get away."

Vernet stepped up to the quivering motor. At the wheel sat a young man, quite composed. In the tonneau, a veiled woman reclined at ease. In her hands she held a brown paper package.

She leaned toward Vernet, and spoke a single word to him. Duvall did not hear what it was; but its effect upon the Prefect's man was instantaneous--electrical. He stepped back and raised his hat. "Pardon, Madame," he said, and the Pasquet rolled through the gate and into the streets of Paris unmolested.

Duvall had sprung forward, and, as he did so, swept the occupants of the car with his electric searchlight. Suddenly he drew back in amazement, just as Vernet allowed the car to pa.s.s on. He could scarcely believe that what he saw was a reality. There was the big black car, its body and wheels plentifully bespattered with the identifying red stain--and there, at the wheel, sat Alphonse Valentin, while the veiled woman in the rear was--Grace!

He did not know it was Grace--he did know that it was the woman who had been with Valentin in his room, who had brought the message from the kidnappers to Mr. Stapleton, who, in some far off and intangible way, reminded him of Grace.

There she sat, in her hand the package containing Mr. Stapleton's money--and Vernet doffed his cap to her, and permitted her to go on! Was this woman, then, hoodwinking even the police?

He sprang to Vernet's side. "Stop them!" he cried, in a hoa.r.s.e voice.

"They are the ones I am after."

Vernet shook his head. "Impossible, Monsieur. They are given safe conduct by Monsieur the Prefect himself."

"But--they are thieves--kidnappers!"

Vernet shrugged his shoulders. "It may be so, Monsieur Duvall; but my orders are to let them pa.s.s."

The detective ground his teeth, helpless. His scheme for identifying the criminals had worked perfectly. He had found them, only to see both them and Mr. Stapleton's hundred thousand dollars as well slip quietly through his fingers. He cursed the whole police force of Paris roundly, in his anger.

The arrival of another car distracted his attention. It was Mr.

Stapleton, hurrying home, in the hope of finding his boy. Duvall did not stop him. The banker was evidently thinking of nothing but his lost son.

Several other cars pa.s.sed. Duvall had no interest in them. He was about to turn away, with the intention of hunting up Mr. Stapleton and learning whether or not the boy had been returned to him, when he heard a familiar voice calling him by name. He turned. It was Monsieur Lefevre, in a big dark green car.

"Mon Dieu! Duvall!" the Prefect cried, in pretended surprise. "You here!

In Paris! Or do my eyes deceive me?"

The detective looked a bit sheepish. He realized that in not calling on his old friend before now, he had been guilty of an apparent rudeness which Monsieur Lefevre might justly resent. "Monsieur," he cried, "it is indeed I." He put out his hand, and grasped that of his old chief warmly. "A little matter of business brought me to Paris. I have only just arrived."

"Indeed." The Prefect's eyes twinkled. "I hope, my dear fellow, that your other engagements will permit you to come and see me before long."

"I shall come this very evening, Monsieur. In fact, I have a matter of the utmost importance to discuss with you. Shall you be at liberty?"

"In an hour, _mon ami_. Until then I have other things to occupy me.

Come to the Prefecture in an hour. I shall be waiting for you. For the present, adieu." He called an order to his chauffeur, and drove rapidly off into the darkness.

Duvall turned on his heel and began to look for a taxicab. "Good night, Vernet," he called out, as he went up the street.

In half an hour, he had reached Mr. Stapleton's house. He found the unfortunate banker striding up and down his library in a towering rage.

"The fellows have deceived me!" he cried. "They have not brought back my boy. Did you see anything of them? Tell me!" He grasped Duvall nervously by the arm.

"The car into which you threw the package of money contained, besides the chauffeur, but one occupant, a woman, did it not?"

"Yes--yes! Did you get her?"

"No."

"Why not? Did your scheme to identify the car fail to work?"

"On the contrary, it worked perfectly. I stopped the car at the barrier.

The woman in it had the package of money in her hand."

"And you did not arrest her! In Heaven's name, why not?"

"The police would not permit me to do so. The woman was the same one who brought you the message last night, the supposed agent of the police.

They allowed her to pa.s.s the gates."

"What?" the banker fairly shouted his question. "This is ridiculous! Is the woman a criminal, or is she a detective? She cannot be both, and if she is the latter why was she in that car, with my money in her hand?"

"I do not know. But I mean to find out very shortly."

"How? I'd like to know!"

"I am going to see the Prefect of Police at once."

Mr. Stapleton sank into a chair, and groaned. "I had hoped to have Jack with me by now. His poor mother is distracted. Isn't there anything, Mr.

Duvall, that you can do?"

"I hope to answer that question better, Mr. Stapleton, after I have seen Monsieur Lefevre. If this woman, and her companion, Valentin, are really the kidnappers, they are in Paris, and we shall be able to lay our hands on them without difficulty. If they are not, your money, at least is safe. I must leave you now; but as soon as I learn anything, I will report to you at once. Good night."

He left the house, more mystified than he had ever been in his life.

From the start, this case had apparently been one in which all the clues led to absurd contradictions, or else to nothing at all.

In fifteen minutes he was at the Prefecture.

Monsieur Lefevre sent out word that he would be occupied for a few moments, and the detective sat down as patiently as possible, to wait.