He had succeeded with five, when the sixth stuck fast in the groove of the clockwork.  Just at that moment, as we judged, either an alarm was raised in the rear, or some panic fear seized on him.  Probably the fellow judged right that the most incriminating pictures of all had by that time been removed, and that the last would only show his back, if it included him at all, or if he came into focus.  Perhaps he had even been able unconsciously to count the flashes at the moment, and knew that before the sixth flash arrived he was on the ledge of the window.  At any rate, he clearly gave up the attempt to remove the sixth, and flung the whole apparatus away from him in a sudden access of horror.  We guessed as much both from the appearance of the spot where the grass was trampled down, and the way the angle of the camera was imbedded forcibly in the soft ground of the shrubbery.”

“And he got away with the rest!” I exclaimed, following it up like a story, but a story in which I was myself an unconscious character.

“No doubt,” the Inspector answered, stroking his chin regretfully.  “And what’s most annoying of all, we’ve every reason to suppose the fellow stole the things only a few minutes before we actually missed them.  For we saw grounds for supposing he jumped away from the spot, and climbed over the wall at the back, cutting his hands as he went with the bottle-glass on the top to prevent intruders.  And what makes us think only a very short time must have elapsed between the removal of the plates and the moment we came upon his tracks is this—­the blood from his cut hands was still fresh and wet upon the wall when we found it.”

“Then you only just missed him!” I exclaimed.  “He got off by the skin of his teeth.  It’s wonderful, when you were so near, you shouldn’t have managed to overtake him!  One would have thought you must have been able to track him to earth somehow!”

“One would have thought so,” the Inspector answered, rather crestfallen.  “But policemen, after all, are human like the rest of us.  We missed the one chance that might have led to an arrest.  And now, what I want to ask you once more is this:  Reflecting over what you’ve heard and read to-day, do you think you can recollect—­a very small matter—­whether or not there were several distinct flashes?”

I shut my eyes once more, and looked hard into the past.  Slowly, as I looked, a sort of dream seemed to come over me.  I saw it vaguely now, or thought I saw it.  Flash, flash, flash, flash.  Then the sound of the pistol.  Then the Picture, and the Horror, and the awful blank.  I opened my eyes again, and told the Inspector so.

“And once more,” he went on, in a very insinuating voice.  “Shut your eyes again, and look back upon that day.  Can’t you remember whether or not, just a moment before, you saw the murderer’s face by the light of the flashes?”

I shut my eyes and thought.  Again the flashes seemed to stand out clear and distinct.  But no detail supervened—­no face came back to me.  I felt it was useless.