Putting aside the somewhat obvious case of Colonel Luttrell who, I was afraid, was hardly likely to take a hatchet to his wife in the middle of a rubber, justifiable though that course might be, I could not at first think of anyone. The trouble was that I did not really know enough about these people. Norton, for instance, and Miss Cole? What were the usual motives for murder? Money? Boyd Carrington was, I fancied, the only rich man of the party. If he died, who would inherit that money? Anyone at present in the house? I hardly thought so, but it was a Point that might bear inquiry. He might, for instance, have left his money to research, making Franklin a trustee. That, with the doctor's rather injudicious remarks on the subject of eliminating 80 per cent of the human race, might make out a fairly damning case against the red-haired doctor. Or possibly Norton or Miss Cole might be a distant relative and would inherit automatically. Farfetched but possible. Would Colonel Luttrell, who was an old friend, benefit under Boyd Carrington's will? These possibilities seemed to exhaust the money angle. I turned to more romantic possibilities. The Franklins. Mrs. Franklin was an invalid. Was it possible that she was being slowly poisoned - and would the responsibility for her death be laid at her husband's door? He was a doctor; he had opportunity and means, no doubt. What about motive? An unpleasant qualm shot across my mind as it occurred to me that Judith might be involved. I had good reason to know how businesslike their relations were - but would the general public believe that? Would a cynical police officer believe it? Judith was a very beautiful young woman. An attractive secretary or assistant had been the motive for many crimes. The possibility dismayed me.

I considered Allerton next. Could there be any reason for doing away with Allerton? If we had to have a murder, I would prefer to see Allerton the victim! One ought to be able to find motives easily for doing away with him. Miss Cole, though not young, was still a good-looking woman. She might, conceivably, be actuated by jealousy if she and Allerton had ever been on intimate terms, though I had no reason to believe that that was the case. Besides, if Allerton was X - I shook my head impatiently. All this was getting me nowhere. A footstep on the gravel below attracted my attention. It was Franklin walking rapidly towards the house, his hands in his pockets, his head thrust forward. His whole attitude was one of dejection. Seeing him thus, off guard, I was struck by the fact that he looked a thoroughly unhappy man.

I was so busy staring at him that I did not hear a footfall nearer at hand and turned with a start when Miss Cole spoke to me.

"I didn't hear you coming," I explained apologetically as I sprang up. She was examining the summerhouse.