It being the luncheon hour, FrÉmy and myself ate our meal at the highly popular restaurant, the Taverne Joseph, close to the Bourse, where the cooking is, perhaps, the best in Brussels and where the cosmopolitan, who knows where to eat, usually makes for when in the Belgian capital.

After our coffee, cigarettes, and a "triple-sec" each, we strolled round to the General Post Office. As we approached that long flight of granite steps I knew so well, a poor-looking, ill-dressed man with the pinch of poverty upon his face, and his coat buttoned tightly against the cold, edged up to my companion on the pavement and whispered a word, afterwards hurrying on.

"Our interesting friend has not been here yet," the detective remarked to me. "We will have a talk with the clerk at the Poste Restante."

Entering the great hall, busy as it is all day, we approached the window where letters were distributed from A to L, and where sat the same pleasant, fair-haired man sorting letters.

"Bon jour, m'sieur!" he exclaimed, when he caught sight of FrÉmy. "What weather, eh?"

The great detective returned his greetings, and then putting his head further into the window so that others should not overhear, said in French:

"I am looking for an individual, an Englishman, name of Bryant, and am keeping watch outside. He is wanted in England for a serious offence. Has he been here?"

"Bryant?" repeated the clerk thoughtfully.

"Yes," said FrÉmy, and then I spelt the name slowly.

The clerk reached his hand to the pigeon-hole wherein were letters for callers whose names began with B, and placing them against a little block of black wood on the counter before him, looked eagerly through while we watched intently.

Once or twice he stopped to scrutinise an address, but his fingers went on again through the letters to the end.

"Nothing," he remarked laconically, replacing the packet in the pigeon-hole. "But there has been correspondence for him. I recollect—a thin-faced man, with grey hair and clean shaven. Yes. I remember him distinctly. He always called just before the office was closed."

"When did he call last?" asked FrÉmy quickly.

"The night before last, I think," was the man's answer. "A lady was with him—a rather stout English lady."

We both started.

"Did the lady ask for any letters?"

"Yes. But I forget the name."

"Petre is her right name," I interrupted. Then I suggested to FrÉmy: "Ask the other clerk to look through the letter 'P.'"

"Non, m'sieur!" exclaimed the fair-haired employÉe. "The name she asked for was in my division. It was not P."

"Then she must have asked for a name that was not her own," I said.

"And it seems very much as though we have lost the gang by a few hours," FrÉmy said disappointedly. "My own opinion is that they left Brussels by the Orient Express last night. They did not call at the usual time yesterday."

"They may come this evening," I suggested.

"Certainly they may. We shall, of course, watch," he replied.

"When the man and woman called the day before yesterday," continued the employÉe, "there was a second man—a dark-faced Indian with them, I believe. He stood some distance away, and followed them out. It was his presence which attracted my attention and caused me to remember the incident."

FrÉmy exchanged looks with me. I knew he was cursing his fate which had allowed the precious trio to slip through his fingers.

Yet the thought was gratifying that when the express ran into the Great Westbahnhof at Vienna, the detectives would at once search it for the fugitives.

My companion had told me that by eight o'clock we would know the result of the enquiry, and I was anxious for that hour to arrive.

Already FrÉmy had ordered search to be made of arrivals at all hotels and pensions in the city for the name of Bryant, therefore, we could do nothing more than possess ourselves in patience. So we left the post office, his poverty-stricken assistant remaining on the watch, just as I had watched in the cold on the previous night.

With my companion I walked round to the big CafÉ Metropole on the Boulevard, and over our "bocks," at a table where we could not be overheard, we discussed the situation.

That big cafÉ, one of the principal in Brussels, is usually deserted between the hours of three and four. At other times it is filled with business men discussing their affairs, or playing dominoes with that rattle which is characteristic of the foreign cafÉ.

"Why is it," I asked him, "that your chief absolutely refuses to betray the identity of the girl Marie Bracq?"

The round-faced man before me smiled thoughtfully as he idly puffed his cigarette. Then, shrugging his shoulders, he replied:

"Well, m'sieur, to tell the truth, there is a very curious complication. In connection with the affair there is a scandal which must never be allowed to get out to the public."

"Then you know the truth—eh?" I asked.

"A portion of it. Not all," he replied. "But I tell you that the news of the young lady's death has caused us the greatest amazement and surprise. We knew that she was missing, but never dreamed that she had been the victim of an assassin."

"But who are her friends?" I demanded.

"Unfortunately, I am not permitted to say," was his response. "When they know the terrible truth they may give us permission to reveal the truth to you. Till then, my duty is to preserve their secret."

"But I am all anxiety to know."

"I quite recognise that, M'sieur Royle," he said. "I know how I should feel were I in your position. But duty is duty, is it not?"

"I have assisted you, and I have given you a clue to the mystery," I protested.

"And we, on our part, will assist you to clear the stigma resting upon the lady who is your promised wife," he said. "Whatever I can do in that direction, m'sieur may rely upon me."

I was silent, for I saw that to attempt to probe further then the mystery of the actual identity of Marie Bracq was impossible. There seemed a conspiracy of silence against me.

But I would work myself. I would exert all the cunning and ingenuity I possessed—nay, I would spend every penny I had in the world—in order to clear my well-beloved of that terrible suspicion that by her hand this daughter of a princely house had fallen.

"Well," I asked at last. "What more can we do?"

"Ah!" sighed the stout man, blowing a cloud of cigarette smoke from his lips and drawing his glass. "What can we do? The Poste Restante is being watched, the records of all hotels and pensions for the past month are being inspected, and we have put a guard upon the Orient Express. No! We can do nothing," he said, "until we get a telegram from Vienna. Will you call at the PrÉfecture of Police at eight o'clock to-night? I will be there to see you."

I promised, then having paid the waiter, we strolled out of the cafÉ, and parted on the Boulevard, he going towards the Nord Station, while I went along in the opposite direction to the Grand.

For the appointed hour I waited in greatest anxiety. What if the trio had been arrested in Vienna?

That afternoon I wrote a long and encouraging letter to Phrida, telling her that I was exerting every effort on her behalf and urging her to keep a stout heart against her enemies, who now seemed to be in full flight.

At last, eight o'clock came, and I entered the small courtyard of the PrÉfecture of Police, where a uniformed official conducted me up to the room of Inspector FrÉmy.

The big, merry-faced man rose as I entered and placed his cigar in an ash tray.

"Bad luck, m'sieur!" he exclaimed in French. "They left Brussels in the Orient, as I suspected—all three of them. Here is the reply," and he handed me an official telegram in German, which translated into English read:

"To PrÉfet of Police, Brussels, from PrÉfet of Police, Vienna:

"In response to telegram of to-day's date, the three persons described left Brussels by Orient Express, travelled to Wels, and there left the train at 2.17 this afternoon. Telephonic inquiry of police at Wels results that they left at 4.10 by the express for Paris."