As the action has now shifted to the upper floor, a diagram of this second story is now in order.

As you will see, a straight glimpse is given down either gallery from the arches opening into the broad corridor into which Mr. Gryce had stepped on leaving the central staircase.  He had therefore only to choose which of the two would better repay his immediate investigation.

He decided upon the northern one, which you will remember was the one holding the tapestry; since, to find anybody there, no matter whom, would certainly settle the identity of the person responsible for that flying arrow.  For, as all conceded, too little time had elapsed between its delivery and the discovery of the victim for the quickest possible attempt at escape to have carried the concealer of the bow very far from the spot where he had thrown it.  It was possible—­just possible—­that he might have got as far as one of the four large rooms opening into the corridor stretching across the front, but that he was not in the gallery itself Mr. Gryce soon convinced himself by a rapid walk through its entire length.

That he did not follow up this move by an immediate searching of the rooms I have mentioned was owing to a wish he had to satisfy himself on another point first.

What was this point?

In passing along the rear on his way to this gallery, he had noticed the narrow staircase opening not a dozen feet away to his left.  This undoubtedly led down to the side-entrance.  If by any chance the user of the bow had fled to the rear instead of to the front, he would be found somewhere on this staircase, for he never could have got to the bottom before the cry of “Close the doors!  Let no man out!” rendered this chance of immediate exit unavailable.  So Mr. Gryce retraced his steps, and barely stopping to note the boy eying him with eager glances from the doorway of Room A, he approached the iron balustrade guarding the small staircase, and cautiously looked over.

A man was there!  A man going down—­no, coming up; and this man, as he soon saw from his face and uniform, was Correy the attendant.

“So that is where you were,” he called down as he beckoned the man up.

“As near as I can remember.  I was on my way in search of Mr. Jewett, for whom I had a message, and had got as far as you saw me, when I heard a cry of pain from somewhere in the gallery.  This naturally quickened my steps and I was up and on this floor in a jiffy.”

“Did you notice, as you stepped from the landing, whether the boy staring at us from the doorway over there was facing just as we see him now?”

“He was.  I remember his attitude perfectly.”

“Coming out of the door—­not going in?”

“Sure.  He was on the run.  He had heard the cry too.”

“And followed you into the gallery?”

“Preceded me.  He was on the scene almost as soon as the man who stepped in from the adjoining section.”