Brett promptly cleared the situation by explaining to Sir Hubert, in a few words, the reason for his unexpected presence, and when the Major-General learnt the name of the distinguished personage who had sent Lord Fairholme to the barrister he expressed a ready acquiescence in the desire to utilise his services. Nor was the effect of such a notable introduction lost on Mr. Winter, whose earlier knowledge of the barrister's remarkable achievements in unravelling the tangled skein of criminal investigation was now supplemented by a certain amount of awe for a man who commanded the confidence of His Majesty's Government.

"Well," said Sir Hubert Fitzjames, with the brisk animation of one accustomed to utter commands that must be instantly obeyed, "we will now proceed to business."

For the moment no one spoke. The Scotland Yard detective evidently wished his distinguished colleague to take the lead. No sooner did Brett perceive this than he rose, bowed politely to Miss Talbot and her uncle, and said—

"The first thing to do is to trace the whereabouts of Mr. Talbot, and this should be a comparatively easy task. The other features of this strange occurrence impress me as highly complex, but it is far too early a stage in the investigation to permit any definite opinion being expressed at this moment."

Every one seemed to be surprised by Brett's attitude.

"Where are you going to, sir?" asked Mr. Winter.

"That depends largely upon you," was the smiling reply. "If you come with me we will go direct to Albert Gate, but if you decide to prosecute further inquiries here, I will await your arrival at my flat."

"That is as much as saying that there are no facts worth inquiring into to be learnt here?"

"Exactly so. Miss Talbot has told me all that is material to our purpose. Her brother was unexpectedly sent for after dinner on Monday night, and left the house hurriedly, without affording any clue to his subsequent proceedings beyond that contained in a brief note sent to him by Mehemet Ali Pasha. Indeed, it was impossible for him to afford any explanation, as he himself was quite unprepared for the summons. Meanwhile, every moment lost in the endeavour to follow up his movements is precious time wasted."

The barrister's manner, no less than his words, impressed Mr. Winter so greatly that he too rose from the seat which he had occupied, with the intention of conducting a long and careful examination of each member of the household.

"Then I will come with you at once," he said.

"Oh," cried the Major-General, "I understood you to say as we came here that there were many questions which required immediate inquiry in this house, on the principle that the movements of the missing man should be minutely traced from the very commencement."

Mr. Winter looked somewhat confused, but Edith Talbot broke in—

"I think, uncle dear, it would be well to defer to Mr. Brett's judgment."

"Do you really believe," she said, turning to the barrister, "that you will soon be able to find my brother?"

"I am quite sure of it," he replied, and the conviction in his tone astonished the professional detective, whilst it carried a message of hope to the others. Even Sir Hubert, for some reason which he could not explain, suddenly experienced a strong sense of confidence in this reserved, distinguished-looking man. He stepped forward eagerly and held out his hand, saying—

"Then we will not detain you, Mr. Brett. Act as you think fit in all things, but do let us have all possible information at the earliest moment. The suspense and uncertainty of the present position of affairs are terribly trying to my niece and myself." The old soldier spoke with dignity and composure, but his lips quivered, and the anguish in his eyes was pitiful.

Brett and Mr. Winter quitted the house; they hailed a hansom, and drove rapidly towards Albert Gate.

"Do you know," said the man from Scotland Yard, breaking in on his companion's reverie, "you surprised me by what you said just now, Mr. Brett?"

"I thought you were too old a hand to be surprised at anything," was the reply.

"Oh, come now, you know well enough what I mean. You said you thought it would be a comparatively simple matter to find Mr. Talbot, whilst the other features of the crime are very complex. Now the affair, thus far, impresses me as being the exact opposite to that statement. The crime is simple enough. A clever gang of thieves get into the place by working some particularly cool and daring confidence game. They don't hesitate at murder to cover up their tracks, and they make away with the plunder under the very noses of the police. All this may be smart and up-to-date in its methods, but it is not unusual. The difficult question to my mind is, what have they done with Mr. Talbot, and how did they succeed in fooling him so completely as to make him what one might almost call a party to the transaction?"

The barrister pulled out a cigar-case.

"Try one of these, Winter," he said. "You will find them soothing."

"I never smoke whilst on business," was the testy reply.

"I invariably do." He proceeded to light a cigar, which he smoked with zest.

"I do not know how it is," went on Mr. Winter, "but whenever I happen to meet you, Mr. Brett, in the course of an inquiry, I always start by being very angry with you."

"Why?" There was an amused twinkle in Brett's eyes, which might have warned the other of a possible pitfall.

"Because you treat me as if I were a precocious youth. You listen to my theories with a sort of pitying indulgence, yet I have the reputation of being one of the best men in Scotland Yard, or I should not have been put on this job. And I am older than you, too."

"I may surely pity you," said Brett, "even if I don't indulge you too much."

"There you go again," snapped the detective. "Now, what is there silly about my theory of the crime, I should like to know."

"You shall know, and before you are much older. Bear with me for a little while, I beg of you. You may be right, and I may be quite wrong, but I think there is much beneath the surface in the investigations we are now pursuing. My advice to you is to drop all preconceived theories, to note every circumstance, however remote it may appear in its bearing upon events, and in any case not to act precipitately. Whatever you do, don't arrest anybody."

"But," said the other, somewhat mollified by Brett's earnestness, "half a dozen people may be arrested at any moment."

"Pray tell me how?"

"Descriptions of the stolen diamonds and of the suspected persons are in every police office in Great Britain and in most Continental centres by this time. Passengers by all steamers are most carefully scrutinised. Every pawnbroker and diamond merchant in the country is on the look-out, and, generally speaking, it will be odd if somebody does not drop into the net before many hours have passed."

"It will, indeed," murmured Brett; "and no doubt the somebody in question will experience a certain amount of inconvenience before he proves to you that he had nothing whatever to do with the matter. Now, don't answer me, Winter, but ponder seriously over this question: Do you really think that the intelligence which planned and successfully carried through an operation of such magnitude will be trapped by plain-clothes constables watching the gangways of steamships, or by any pawnbroker who has ever lent half the value of a pledge?"

Almost impatiently the barrister waved the subject out of the hansom, and the detective had sense enough to leave him alone during the few remaining minutes before the vehicle pulled up near the Albert Gate mansion.

Brett stopped the driver some little distance short of the house itself, as he did not wish to attract the attention of a knot of curious sightseers in the street. He asked Winter to precede him and make known the fact that he was coming, so that there would be no delay at the door. This the detective readily agreed to, and Brett rapidly took in the main external features of the house which had become the scene of such a remarkable tragedy.

It was a palatial structure, built on the sombre lines of the Early Victorian period. Miss Talbot's brief description of the measures taken to protect its occupants from interference was fully borne out by its aspect. There was no access to the basement; the main entrance was situated at the side; all the ground-floor and first-storey windows facing into the street were fitted with immovable wooden venetians. Presumably those on the Park side were similarly secured, whilst the back wall abutted on to that of another mansion, equally large and strongly built, tenanted by a well-known peer.

Truly, it required a genius almost unrivalled in the annals of crime to murder four people and steal diamonds worth millions in such a place whilst guarded by twelve London policemen and under the special protection of the Home Office.

The appearance of Winter at the door caused the gaping idlers in the street to endeavour to draw nearer to the mysterious portals. Thereupon three policemen on duty outside hustled the mob back, and Brett took advantage of the confusion thus created to slip to the doorway almost unperceived. One of the police constables turned round to make a grab at him, but a signal from a confrÈre inside prevented this, and Brett quickly found himself within a spacious entrance hall with the door closed and bolted behind him.

Winter was talking to two uniformed inspectors, to whom he had explained the barrister's mission and credentials.

"We have here, Mr. Brett," he said, "Inspector Walters, who was on duty until ten o'clock on Monday night, and Inspector Sharpe, who relieved him. They will both tell you exactly what took place."

"Thank you," said the barrister, "but it will expedite matters if you gentlemen will first accompany me over the scene of the crime. I will then be able to understand more accurately what happened. Suppose we start here. I presume that this is where the police guard was stationed?"

Inspector Walters assumed the rÔle of guide.

"I was in charge of the first guard established a month ago," he said, "and the arrangements I then made have been adhered to without deviation night and day ever since."

From the outer door a short passage of a few feet led up half a dozen steps into a large reception room, the entrance to which was closed by a light double door, half glass. On both sides of the first short passage were two small apartments, such as are often used in London mansions for the purposes of cloak-rooms. The doors from these rooms opened into the inner hall. A large dining-room was situated on the left or Park side, and on the right was a breakfast or morning-room. At the back of the reception hall a handsome staircase led from left to right to the upper floors, whilst a doorway beneath the staircase gave access to the kitchens and basement offices.

"Here," said the inspector, pointing to the foot of the staircase, "two police-constables were constantly stationed. Another stood there," indicating the passage to the kitchen, "and a fourth at the glass door. As the outer basement entrance was not only securely fastened by bolts and bars, but actually bricked up inside, it was absolutely impossible for any person to enter or leave the house save by the front door, nor could any one go from the kitchen to the upper part of the house without passing under the observation of all four constables. I arranged my guards in military fashion, having three men for each post, with one hour on duty and two hours off, but the same men were never on guard together at definite hours, as they were relieved at varying times. You will understand that I considered it a very responsible task to safeguard these premises, and thought it best to render it impossible for any section of the force under my command to take part in a conspiracy, although such a thing was in itself most improbable."

They then ascended the staircase and found themselves on the first floor.

There were six spacious apartments on this storey, and all of them had originally opened on to the landing. The special precautions taken to guard the diamonds of the Turkish mission had altered all that. Five doorways had been bricked up, the result being that admission to the whole set of rooms could only be obtained through the first door that faced the top of the staircase.

This apartment was luxuriously furnished, and Inspector Walters explained that the Turkish Envoy and his suite passed the working hours of each day there after they had personally thrown open the other apartments to the diamond polishers and unlocked the safes in which the gems were stored, when work ceased on the previous day.

"His Excellency," said the inspector, "kept the keys of this room and the others, together with those of the safes, in his own possession night and day. He slept upstairs, and so did the other two gentlemen. No one was allowed to come to this floor except the confidential servant, named Hussein, who used to bring coffee, cigars, and newspapers or other things the gentlemen might require, together with their lunch in the middle of the day. The workmen brought their lunch with them, so that they came in and out once a day only."

"Where did this confidential servant sleep?" said Brett.

"I believe he used to lie curled up on the rug outside his Excellency's door."

"And the other servants?"

"They all slept in the basement."

"What were they, Turks or Christians?"

"Well, sir," said the inspector with a smile, "two of them were Turks in costume, whilst three were Christians in appearance. That is the best I can say for the Christians, as they were Frenchmen, though certainly the cook was a first-rate chef. Of course, we all got our meals here whilst on duty."

"Did his Excellency and the other members of the mission eat food prepared in the ordinary way?"

"Oh, yes; they appreciated French dishes as keenly as anybody might do."

"It was in this room, then," continued Brett, "that the murders took place?"

"Yes; I suppose that must be so," said the inspector. "But my friend here," pointing to Inspector Sharpe, "can tell that part of the story better than I can."

They passed into the inner rooms, which were quite silent and deserted, and presented a strange appearance considering the character of the house and its locality. Although the ceilings were decorated with beautiful paintings and fringed with superbly emblazoned mouldings, although the walls were papered with material that cost as much per yard as good silk, each apartment was occupied with workmen's benches, and curious devices for cutting and polishing diamonds.

In the first room were two small safes, one of which was intended to receive the gems under treatment at the close of each day's work; the other held certain valuable materials required in the diamond cutter's operations. Three of the rooms were on the Park side, and it was here that the small colony of skilled artisans had been installed.

The other two rooms were not tenanted, nor had any communicating doors been broken through the walls in order to gain access to them.

The windows of the three apartments occupied by the workmen were not only guarded by strong iron bars, but possessed the additional security of external wire blinds of exceedingly small mesh. Each window admitted plenty of light, and could be raised to allow a free circulation of air, but it was seemingly quite impossible for any active communication to take place with the outside. The three rooms looked out over a small enclosed lawn, which was separated from the park by a brick wall surmounted by iron railings. All the fireplaces had been closed with bricks and mortar.

"You will see, sir," said the inspector, when he had called Brett's attention to these details, "that mysterious though the murders were, they were as nothing compared with the disappearance of the diamonds. Every person who came downstairs was most carefully and methodically searched each time he passed the constable on duty at the bottom. It may be admitted that a few small stones could be so secreted as to escape observation, but some of these stones were so large that such a notion is not to be thought of, whilst the size of the great diamond which Mr. Talbot christened the 'Hen's Egg' rendered its transference past the searchers beneath absolutely impossible. There was no humbug about the search, you will understand, Mr. Brett. People had to take their boots off, open their mouths, and hand over their hats, coats, sticks, or umbrellas for inspection. Every part of their clothing was scrutinised, and the contents of their pockets, money, watches, keys, and the rest, thoroughly examined. These were our orders, and they were strictly obeyed, Mr. Talbot himself being the first to insist that the regulation should be carried out rigidly, so far as he was concerned. Why, one day a Cabinet Minister came here to see the diamonds. He was elderly and stout, and did not at all like having to take off his boots, I can assure you, as he nearly got apoplexy whilst lacing them up again."

During the inspector's running comments Brett had carefully scrutinised each of the windows. He at once came to the conclusion, by a simple analysis of the possibilities, that by no other means than through the barrier of iron wire had the diamonds passed out of the house; but the most thorough examination failed to reveal any loophole by which this achievement had been accomplished. He opened each of the windows, tested every iron bar, and saw that the fastenings of the external blind were undisturbed, whilst the fine wire mesh showed no irregularities in its hexagonal pattern wherein any defect would at once be visible.

"We have done all that long since, sir," said the second police officer, smiling at the obviousness of an amateur's method of inspection, for it happened that he had never met the barrister before, though he had often heard of him.

"You have?" said Brett, with the slightest tinge of sarcasm in his voice. "Did you do this?" and he commenced to thump with a clenched fist upon every portion of the external screen that he could reach.

"No, we did not," said the policeman, "and I don't see that it is going to accomplish anything except hurt your hand."

"That may be so," murmured Brett; "but the diamonds went this way and none other."

He tested every portion of one window screen in this manner without effect. Then he approached the second window, and, beginning at the left-hand top corner, did the same thing. Suddenly an exclamation came from the three interested watchers. In the centre of the lower part of the screen Brett's hand made a visible impression upon the iron wire. Using no more force than had been applied to other portions, the blow served to tear a section of the blind about eight inches across. Instantly the barrister ceased operations, and, producing a pocket-microscope, minutely examined the rent.

"I expected as much," he said, taking hold of the torn part of the screen and giving it a vigorous pull, with the result that a small piece, measuring about eight inches by six, came bodily out. "This has been cut away, as you will see, by some instrument which did not even bend the wire. It was subsequently replaced, whilst the fractured parts were sufficiently cemented by some composition to retain this section in its place, and practically defy observation. There was nothing for it but force to reveal it thus early. No doubt in time the composition would have dried, or been washed away, and then this bit of the screen would have fallen out by the action of wind and weather. Here, at any rate, is a hole in your defensive armour." He held out the piÈce de conviction to the discomfited Sharpe, who surveyed it in silence.

It was no part of Brett's business in life, however, to snatch plaudits from astounded policemen.

"This is a mere nothing," he continued. "Of course, there must have been some such means of getting the diamonds off the premises. Let us return to the ante-room and there you can tell me the exact history of events on Monday evening."