The stout, round-faced Frenchman rose, and, bowing with his irritating politeness, answered—

“I wish to consult you, Monsieur Biddulph, upon a confidential matter concerning your wife.”

“What does my wife concern you, pray, sir?” I asked angrily.

“Ah! calm yourself, m’sieur,” he said suddenly, dropping into French; “I am here as your friend.”

“I hardly believe that,” I replied incredulously. “My friend cannot be the accomplice of my enemies. You are acquainted with Reckitt and with Pennington—the men implicated in the recent theft of the diamonds of the Archduchess Marie Louise!”

He started and looked at me quickly.

“What do you know of that?” he inquired, with rather undue eagerness.

“I know more concerning you than you think,” was my firm reply. “And I give you an alternative, Monsieur Guertin. Either you will reveal to me the whole truth concerning those men Reckitt and Forbes and my wife’s connection with them, or I shall telephone to the police, and have you arrested as a member of the gang.”

“My dear monsieur,” he replied, with a good-humoured smile, “I can’t tell you facts of which I possess no knowledge. I am here to make inquiry of you—to——”

“To mislead me further!” I cried angrily. “You and your friends may be extremely clever—you have succeeded in enticing my wife away from her home, and you expect to befool me further. Remember that I nearly lost my life in that grim house in Bayswater. Therefore at least I can secure the arrest of one member of the gang.”

“And you would arrest me—eh?” he asked, looking me straight in the face, suddenly growing serious.

“Yes, I intend to,” I replied, whipping out my revolver from my hip pocket.

“Put that thing away,” he urged. “Be reasonable. What would you profit by arresting me?”

“You shall either speak—tell me the truth, or I will hand you over to the police. I have only to touch this bell”—and I raised my hand to the electric button beside the fireplace—“and a telephone message will call a constable.”

“And you really would give me in charge—eh?” laughed my visitor.

“I certainly intend doing so,” I answered angrily.

“Well, before this is done, let us speak frankly for a few moments,” suggested the Frenchman. “You tell me that you nearly lost your life in some house in Bayswater. Where was that?”

“In Porchester Terrace. What is the use of affecting ignorance?”

“I do not affect ignorance,” he said, and I saw that a change had completely overspread his countenance. “I only wish to know the extent of your knowledge of Reckitt and Forbes.”

“I have but little knowledge of your friends, I’m pleased to say,” was my quick rejoinder. “Let us leave them out of the question. What I desire to know is the whereabouts of my wife.”

He shrugged his broad shoulders.

“I regret that I have no knowledge of where madame may be.”

“But you have!” I cried, facing him angrily. “She is probably with Pennington, her father, who seems to be one of your undesirable fraternity.”

“No, she is not with him, most certainly,” my visitor declared. “I know that for a fact. She is probably with Lewis.”

“And who is this fellow Lewis?” I demanded.

For a moment he was silent.

“I think you had better ask madame, your wife,” he replied at last.

“Do you intend to cast a slur upon her?” I cried, facing him resentfully.

“Not in the least,” was his cool answer. “I have merely replied to your question.”

“And have given me most impertinent advice! Will you, or will you not, tell me who the fellow is?”

“At present, monsieur, I must refuse.”

“Then I shall press the bell, and give you into custody.”

“Ah!” he laughed, “that will be distinctly amusing.”

“For me, perhaps—not for you.”

“Monsieur is at liberty to act as he deems best,” said my visitor.

Therefore, irritated by the fellow’s manner, and in the hope that he would at the eleventh hour relent, I pressed the bell.

It rang loudly, and I heard old Browning go to the telephone beneath the stairs. In a few minutes the constable would arrive, and at least one member of the dangerous gang would be secured.

“Perhaps you will let me pass,” he said, crossing towards the door immediately after I had rung the bell. But I placed myself against it, revolver in hand, preventing him and holding him at bay.

“Very well,” he laughed. “I fear, Mr. Biddulph, that you are not acting judiciously. You refuse to accept my statement that I am here as your friend!”

“Because you, on your part, refuse to reply to my questions.”

But he only shrugged his shoulders again without replying.

“You know quite well where my wife is.”

“Alas! I do not,” the fellow declared emphatically. “It was to obtain information that I called.”

“You cannot deny that you know that pair of criminals, Reckitt and Forbes?”

“I have surely not denied knowledge of them!”

“Yet you refuse to tell me who this man is who enticed my wife from my side—the man who presided over that secret council at the George Hotel at Stamford!”

“I am prepared to be frank with you in return for your frankness, monsieur,” he answered.

But I saw in his evasive replies an intention to mislead me into a belief that he was actuated towards me by friendly motives. Therefore my antagonism increased. He had defied me, and I would give him into custody.

Presently there came a loud knocking at the door, and, upon my opening it, a police-sergeant stood upon the threshold.

“I give this man into custody,” I said, addressing him and pointing to the Frenchman.

“Upon what charge, sir?” asked the burly officer, whose broad shoulders filled the doorway, while I saw a constable standing behind him.

“On suspicion of being associated with the theft of the diamonds of the Archduchess Marie Louise,” I replied.

“Come, monsieur,” laughed my visitor, speaking again in English, “I think we have carried this sufficiently far.” And, placing his hand in his breast-pocket, he produced a small folded yellow card bearing his photograph, which he handed to me. “Read that!” he added, with a laugh of triumph.

I saw that the printed card was headed “PrÉfecture de Police, Ville de Paris,” and that it was signed, countersigned, and bore a large red official seal.

Quickly I scanned it, and, to my abject dismay, realized that Henri Guertin was chief of the first section of the sÛretÉ—he was one of the greatest detectives of France!

I stammered something, and then, turning to the sergeant, red and ashamed, I admitted that I had made a mistake in attempting to arrest so distinguished an official.

The two metropolitan officers held the card in their hands, and, unable to read French, asked me to translate it for them, which I did.

“Why,” cried the sergeant, “Monsieur Guertin is well known! His name figures in the papers only this morning as arresting two Englishmen in Paris for a mysterious murder alleged to have been committed in some house in Bayswater!”

“In Bayswater!” I gasped. “In Porchester Terrace?”

“Yes,” replied the famous French detective. “It is true that I know Reckitt and Forbes. But I only knew them in order to get at the truth. They never suspected me, and early yesterday morning I went to the snug little apartments they have in the Rue de Rouen, and arrested them, together with two young Frenchmen named Terassier and Brault. Concealed beneath a loose board in the bedroom of the last-named man I found the missing gems.”

“Then Terassier and Brault were the two men who met the others in Stamford, and carried the diamonds across to the Continent, intending to dispose of them?”

“Exactly. There was a hitch in disposing of them in Amsterdam, as had been intended, and though the diamonds had been knocked from their settings, I found them intact.”

He told me that Forbes was the actual thief, who had so daringly travelled to Finsbury Park and collected the tickets en route. He had practically confessed to having thrown the bag out to Reckitt and Pennington, who were waiting at a point eight miles north of Peterborough. They had used an electric flash-lamp as they stood in the darkness near the line, and the thief, on the look-out for the light, tossed the bag out on to the embankment.

“Then my father-in-law is a thief!” I remarked, with chagrin, when the sergeant and constable had been dismissed. “It was for that reason my wife dare not face me and make explanation!”

“You apparently believe Arnold Du Cane, alias Winton, alias Pennington, to be Sylvia’s father—but such is not the case,” remarked the great detective slowly. “To his career attaches a very remarkable story—one which, in my long experience in the unravelling of mysteries of crime, has never been equalled.”

“Tell me it,” I implored him eagerly. “Where is my poor wife?”