She had overheard what must have sounded like a struggle, and there was the dead man, his skull crushed by a blow.

Everything pointed directly toward me from her point of view--motive, opportunity.

Who else could it be?
Even I, anxious as I was, could not answer that question.

I had seen no one, was not aware the dead man had an enemy about the place, could discover no clue except that bit of damp clay on the stairs.

Yes, and my own boots were stained with it also--only I knew that lump never came from mine.
These thoughts swept across my mind in lightning-like flashes, but brought no solution to the problem.