At the end of these inquiries, he paused and looked hard at me.

“Now, Miss Callingham,” he said again, peering deep into my eyes, “I want you to concentrate your mind very much, not on this Picture you carry so vividly in your own brain, but on the events that went immediately before and after it.  Pause long and think.  Try hard to remember.  And first, you say there was a great flash of light.  Now, answer me this:  was it one flash alone, or had there been several?”

I stopped and racked my brain.  Blank, blank, as usual.

“I can’t remember,” I faltered out, longing terribly to cry.  “I can recall just that one scene, and nothing else in the world before it.”

He looked at me fixedly, jotting down a few words in his note-book as he looked.  Then he spoke again, still more slowly: 

“Now, try once more,” he said, with an encouraging air.  “You saw this man’s back as he was getting out of the window.  But can’t you remember having seen his face before?  Had he a beard? a moustache? what eyes? what nose?  Did you see the shot fired?  And if so, what sort of person was the man who fired it?”

Again I searched the pigeon-holes of my memory in vain, as I had done a hundred times before by myself.

“It’s no use,” I cried helplessly, letting my hands drop by my side.  “I can’t remember a thing, except the Picture.  I don’t know whether I saw the shot fired or not.  I don’t know what the murderer looked like in the face.  I’ve told you all I know.  I can recall nothing else.  It’s all a great blank to me.”

The Inspector hesitated a moment, as if in doubt what step to take next.  Then he drew himself up and said, still more gravely: 

“This inability to assist us is really very singular.  I had hoped, after Dr. Thornton’s report, that we might at last count with some certainty upon arriving at fresh results as to the actual murder.  I can see from what you tell me you’re a young lady of intelligence—­much above the average—­and great strength of mind.  It’s curious your memory should fail you so pointedly just where we stand most in need of its aid.  Recollect, nobody else but you ever saw the murderer’s face.  Now, I’m going to presume you’re answering me honestly, and try a bold means to arouse your dormant memory.  Look hard, and hark back.—­Is that the room you recollect?  Is that the picture that still haunts and pursues you?”

He handed me the photograph he held in his fingers.  I took it, all on fire.  The sight almost made me turn sick with horror.  To my awe and amazement, it was indeed the very scene I remembered so well.  Only, of course, it was taken from another point of view, and represented things in rather different relative positions to those I figured them in.  But it showed my father’s body lying dead upon the floor; it showed his poor corpse weltering helpless in its blood; it showed myself, as a girl of eighteen, standing awestruck, gazing on in blank horror at the