The luggage which had been left at Victoria Station on the fatal day was, of course, seized by the police. They searched it thoroughly in the hope that they would find something useful to them in the shape of letters or memoranda.

Of letters there were only two, brief ones from Iris Deane, in which she expressed her determination of sticking out for her ten thousand pounds. As we know, in the end she gave way and accepted seven.

But they did find one priceless thing, and that was a diary, bound in red leather, a small volume as to the size of the page, but very bulky. It had evidently been the dead man's habit to keep a fairly close record of his doings, for it was numbered, and contained entries from some date in May 1919 up to July 3rd, the day before he left the hotel, and announced to the manager that he intended to take a late train to Brighton.

For the twentieth time since he had discovered this important piece of evidence, Mr. Bryant sat in his room at Scotland Yard, reading and re-reading the entries which he knew almost by heart.

With the entries, before the visit to London, Bryant had no concern. They recorded trifling events which had no reference to the tragedy at Cathcart Square. There was, of course, allusion to the letter from Roderick which had so startled his family, the letter announcing his engagement to the chorus girl, Iris Deane, and his fixed resolve to make her his wife. There was a note of a family council, in which the elder brother was deputed to approach the young woman herself, with the object of buying her off.

There were a few records of his first days in London, after a long absence, his visits to his clubs, his meeting with old pre-war acquaintances, his first interview with Iris Deane, the difficulty of arranging further interviews either at his hotel or her flat, owing to the fear of Roddie popping in unexpectedly.

Then came the whimsical record of his strolling round Kensington, halting opposite the house with the board announcing that it was to be let furnished, his interview with the accommodating caretaker who, in return for a very handsome douceur, gave him a duplicate key to enter the house at any time he liked. He had casually mentioned to Miles that his name was Sanderson.

The Major seemed childishly pleased over what he considered a very astute move, especially the giving of another name. Here in this quiet backwater of the world, for so it would seem to a man of his wealth and position, he could continue his negotiations with the somewhat obstinate Iris. In the portion of the diary concerned with the grasping and frivolous young chorus-girl, Bryant was not greatly interested. He had learned this already from Iris Deane, whom he had interviewed a few times, and Reginald Davis.

He turned from the bulky little volume, the pages of which were covered with the Major's small, rather methodical handwriting, to a slenderer book lying beside him. Into this had been copied all the extracts bearing on the relations between the dead man and Mrs. Spencer, otherwise Stella Keane, otherwise Norah Burton.

The first entry recorded the dinner-party at Carlton House Terrace, when he had been struck by the remarkable likeness of his friend's wife to the pretty adventuress at Blankfield, who had driven his old friend, Jack Pomfret, to his death; his endeavours to startle her by allusions to that garrison town.

An important entry was that of his interview with his old acquaintance at the club, Gilbert Fairfax, from whom he had learned something of the atmosphere of the L'Estrange flat in Elsinore Gardens, the branding of Tommie Esmond as a card-sharper, the flight of the fat little man to the Continent, the visit of Stella Keane to Charing Cross Station to bid the detected cheat farewell. There was a comment upon this fact: "Whether she is Norah Burton or not, her intimacy with the L'Estrange set, her solicitude for Tommie Esmond, are sufficient to make her unfit to be the wife of a straight, honest fellow like my old friend Guy Spencer."

There followed further entries, relating his interview with Bryant, the confirmation by the detective that Stella Keane was Norah Burton, that George Dutton, the keeper of the obscure little bucket-shop in the City, was the same George Burton who had been arrested at Blank-field on a charge of forgery, and who, thanks to one of the cleverest advocates at the criminal bar, had got off with a very light sentence.

There was a full record of the long interview with Mrs. Spencer, in which she had been finally confounded, and forced to confession, of her acceptance of his terms, of the words she had uttered when, while rather regretting that things could not go on as they were, lamenting the fact that her accuser had ever been born, she was not at all satisfied with her present environment, and would experience a certain measure of relief in quitting it for a more congenial sphere.

On the day he had parted from her, the day on which she had yielded to his inflexible determination that she must remain under her husband's roof as short a time as possible, he recorded the fact that, up to the present moment, he had not made up his mind as to the precise way in which he was going to bring about the separation. He wanted to choose the way which would least hurt Guy.

There had flashed through his mind that, in addition to the confession she was about to make to him of her whole career, she should confess to her husband that she was not legally his wife, being in reality the wife of George Burton, alias George Dutton. There followed here a note. "I am convinced she and this rascal were married, the sister and cousin dodges were always a fake. I must see Parkinson to find out if he can ferret out anything on that point. But the time is short. In a week I must be ready for action."

A further entry showed that he had called on Parkinson with this object, only to learn that the detective had gone on an important mission abroad, and could undertake no further work till his return, which would be some ten days hence. That idea therefore had to be dismissed. He must think out some other plan.

Then came the last and most important entry of all, dated on the fourth of July, written no doubt a few hours before he took his luggage to Victoria Station.

"I meet Norah Burton, I always think of her by that old name, at Cathcart Square at six o'clock to-night. I have given the caretaker a holiday to keep him out of the way. I have drawn up two copies of the confession, one of which she is to sign. I have also drawn up an undertaking on my part to keep her from want in case Guy should prove obdurate. But this I am sure he will not do. Besides, if she is his wife, and thinking it over, I have my doubts as to whether she was ever really married to Burton, he would have to support her, in spite of her unsavoury associations."

Bryant paused for a moment as he finished this paragraph to reflect a little. Personally, he did not believe that she was the wife of George Burton; in his opinion, their association had been the result of mutual interests. With this knowledge hanging over her head, she would hardly have been daring enough to go through the ceremony of marriage with two other men. Anyway, it was a debatable point.

Moreover, Burton, like most criminals, would be very wide awake and calculating. To marry her would be to handicap himself. He could get more out of her by marrying her to a rich man.

Then came the last paragraph of all.

"Now, for my action after the final interview of to-night, when she has signed the confession. I may do one of two things, forbid her to return to her husband's house, and go myself straight to Eaton Place, and break the news to Spencer without any preamble. In that case, I shall take with me some ready money to hand to her, as she will probably have very little upon her.

"And yet I rather shrink from this course; it would be painful for me to watch his agony while I struck such a terrible blow. I will run down to Brighton, drop him a note telling him that an important letter will reach him at his club by registered post to-morrow, that he is on no account to let his wife know he has heard from me till he has read the contents of that registered packet.

"I shall post him the copy of the confession, telling him he can inspect the original at any time he likes, meeting me either in Brighton or London, leaving him to deal with her as he chooses. After all, his is the right to dispose of his private affairs, my duty really ends when I have put him in possession of the facts. My first method must have the effect of creating open scandal at once, by my insisting upon her not returning to Eaton Place.

"He may wish to devise some plan that will create a scandal less open, to save, as far as he can, the disgrace to himself and his family. If I know the man, and here, perhaps, I am arguing from the knowledge only of my own temperament, I should say his love would turn to hatred after he reads that confession. Jack Pomfret was a weaker man than Guy, but he acted as I should have done under the circumstances, and refused all further communication with her, refused to give her the opportunity of denial or explanation.

"Still, there is no knowing to what lengths a deep-rooted infatuation for a fascinating woman will lead a man. In this respect, Guy may be less adamant than Pomfret, although I am sure he will never imitate poor Jack's final weakness. He is too sturdily built for that.

"When confronted with that confession she may plead artfully, and, perhaps to him, convincingly, that while she admits everything contained in it, she was more sinned against than sinning, that she tried to escape from her odious bondage by marrying Jack, and that with his suicide and the frustration of her hopes, she was compelled to return to an environment which she loathed. He might consent to believe and forgive, although to me such a thing seems incredible, impossible."

Bryant closed the book on the last entry. That little red-leather volume threw a lurid light on the mystery of Cathcart Square. The exhumed body was found to be that of Major Murchison, wrongly identified in the first instance as that of Reginald Davis. It was all very clear.

That meeting had taken place, and the unfortunate man had been done to death by the precious pair, Norah Burton and the scoundrel brother, cousin or life-long lover, whichever he was. Reginald Davis was an old acquaintance of theirs, had been possibly a more intimate one than the cautious Davis was prepared to admit. They took with them letters addressed to their old friend, they forged a letter from him intimating his intention to commit suicide.

If Davis read of all this in the papers, he was too concerned with his own danger to emerge from his hiding-place and publish the truth to the world. He would be thankful that, through the villainy of others, he could take a new lease of life, unmenaced by detection. Of course, they had never thought of the possibility that Davis would be cleared by the confession of the real criminal. Like Scotland Yard, they were sure he was guilty, and his silence was a matter of certainty.

And slowly Bryant, drawing from the stores of his vast experience, began to construct in his own mind the details of the murder, executed by two desperate criminals, almost driven to the verge of madness by the knowledge that their carefully-laid plans were about to be frustrated by the action of one man.

The woman, the weaker of the two, was probably more disposed to yield to the force and strength of circumstances. Once before, in her marriage to Jack Pomfret, she had had the cup snatched from her lips, and bowed to the inevitable. From the few words recorded in the Major's accusing diary, it would seem that, secured of a modest competence, she was ready a second time to accept her fate.

And then, in that week's interval, it was easy to guess what had happened. She had consulted her old partner in crime, George Burton. He had reasoned, as it turned out, a little shallowly, remove Murchison, and the danger will be past. The resemblance of Murchison to Reginald Davis had occurred to the pair, hence the cunningly prepared letters.

And how was the actual murder accomplished? Had they gone to Cathcart Square together, or had Burton followed her, getting in by means of that broken window-pane at the back? And did they know the Major was alone? In that last interview with Mrs. Spencer, had he let out the fact that he had given the caretaker a holiday, so that they should not be disturbed?

These were side problems that could not be solved at the moment. Only two persons could solve them, and those two, in all probability, would never speak.

But how had they killed him? The Major was a strong, muscular fellow who would fight tenaciously for his life. Norah Burton was a slender woman, almost verging on frailness, George Dutton, to call him by his latest name, was certainly of a muscular build, although of only average height.

Well, of course, they had foreseen and prepared for all that. while talking to him, she had sprayed over him the essence of some overpowering and stupefying drug, and while he was staggering about, dazed and blinded, the man had stepped in and done the rest.

Owing to the absence of the caretaker, they had plenty of time. They had rifled his pockets, taking out of them the money which, according to his diary, he had brought along with him, his personal belongings, the ticket which he had received at the luggage room of Victoria Station, and, of course, the confession which Norah Burton had or had not signed. No doubt, they had also examined his linen and underclothing to make sure that his name was not on them. If it had been, they would have dealt with it by stripping the body.

They had carried it out pretty well, on the whole. There were two things they had not reckoned on. One was the resuscitation of Reginald Davis. The other was the fact that Murchison kept a diary, one of the last things that a man of his sort was likely to do.

Bryant, although not a very emotional man, felt very depressed as he came to the result of his meditations. He felt sure that, if Norah Burton could have had her own way, she would have accepted her fate, gone forth on the world again with the slender pittance that either of the two men, her husband or his friend, would have allowed her.

She had suffered herself to be dominated by a more reckless and criminal spirit, with the result that the life of an honourable man had been taken, and she was already standing at the foot of the gallows.

The pair, only knowing that the body had been exhumed and proved to be that of Hugh Murchison—a terribly disturbing thought to them—but ignorant of the discovery of that incriminating diary, were being closely watched. But they felt sure that nothing could be traced to them, they had hidden their tracks so cleverly, as they thought.

It was now only a question of a few hours as to when they should be taken. And Bryant felt that Guy Spencer should know the truth before anybody else. Poor fellow! He would soften the blow to him as much as he could.

That same evening he went round to Eaton Place, about seven o'clock. He reckoned that he would catch Spencer before he went up to dress for dinner. "Poor devil," thought Bryant, "he won't have much appetite for dinner after he has read through that diary!"

Spencer was in the library, and the detective, whom he had met before in connection with the mystery of Cathcart Square, was shown in. Spencer welcomed him with his usual cordiality.

"Good-evening, Mr. Bryant. Any fresh light upon this terrible thing?"

The footman had left the library door slightly open, after showing Bryant in, and had retired swiftly to his quarters.

He was hardly out of the hall when Stella opened the front-door with her key, and glided noiselessly in. All her movements were noiseless, suggesting, as somebody had once remarked of her, the silent motions of a snake. She always carried a key, declaring that she could not be kept waiting for servants to answer the door.

The library door was open, through the aperture she heard voices, and one of them she recognised. It was that of the Scotland Yard detective, who had cross-examined her very closely as to her various meetings with the dead man. She had been afraid of Bryant. He had looked at her so searchingly, and his manner always conveyed that he knew so much more than he was prepared to disclose.

Bryant was speaking in a low, but very clear voice. Her hearing was singularly acute, and she could catch every word.

"I am come on a very painful errand, Mr. Spencer. There is a small volume here which throws a very clear light on what happened at Cathcart Square on that fatal evening of July the fourth."

Guy's cheerful accents rang out. "You mean you have got a clue, Mr. Bryant. But why painful to me? If you are on the track of the murderer of my poor old friend, nobody will be more rejoiced than I."

Again the low, grave tones of Bryant:

"Mr. Spencer, you will be a very stricken man when you have read through it. Your poor friend left behind him a very copious diary, made up to the morning of the day on which he was murdered. The original is at my office, you can inspect it at any time you like. This is a copy of the entries relating to Cathcart Square. It touches your domestic life very closely, in addition to proving why and by whom he was murdered."

Stella waited to hear no more. Her face had gone livid, she felt shaking in every limb. That her old enemy, Murchison, had left a diary! They had never thought of that possibility. The game was up. She had staked something on her marriage as Norah Burton with Jack Pomfret, and had lost. This time she had staked everything and lost again, but now she had lost liberty and life in addition. There was but one end. She must seek at once the man who had, in a way, been a good and faithful friend, but also her evil genius.

She stole as quietly out of the hall as she had entered it, and hailed a passing taxi. She knew she would never enter the house at Eaton Place again.