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.