“Odd couple over there,” he whispered as the older detective paused to listen.  “Been watching them for the last five minutes.  They pretend to be looking at some old armor, but they are mighty uneasy and keep glancing up at the window overhead as if they would like to jump out.”

Mr. Gryce indulged in one of his characteristic exclamations.  This was the couple whose queer actions he had noticed on the staircase.  “I’ll have a talk with them presently.  Anyone in the rooms opposite?”

“Yes, the Curator.  He’s in Room A, where there are a lot of engravings waiting to be hung.  I guess he was pretty well up to his neck in business when that fellow Correy set up his shout.  And have you noticed that he’s a bit deaf, which is the reason, perhaps, why he was not sooner on the scene?”

“No, I hadn’t noticed.  Anyone else at this end?”

“Only the young couple I speak of.”

Mr. Gryce gave them a second look.  They were by many paces farther from the pedestal from behind which the bow had been flung back of the tapestry than would quite fit in with the theory he had formed, and by means of which he hoped to single out the person who had sent the deadly arrow.  But then, under the stress of fear, people can move very swiftly; and besides, what guarantee did he have that these poor, frightened creatures had located themselves with all the honesty the occasion demanded?  According to Sweetwater there was nobody sufficiently near to notice where they had been at the critical instant, or where they were now.  The student’s back was toward them, and the Curator quite out of sight behind a close-shut door.

With this doubt in his mind, Mr. Gryce started to approach the couple.  As he did so, he observed another curious fact concerning them.  They were neither of them in the place natural to people interested in the contents of the great cases which they had crossed the hall to examine.  Instead of standing where a full view of these cases could be had, they had withdrawn so far behind them that they presented the appearance of persons in hiding.  Yet as he drew nearer and noted their youth and countrified appearance, Mr. Gryce was careful to assume his most benign deportment and so to modulate his voice as to call up the pink into the young woman’s cheek and the deep red into the man’s.  What Mr. Gryce said was this:  “You are interested I see in this show of old armor?  I don’t wonder.  It is very curious.  Is this your first visit to the museum?”

The man nodded; the woman lowered her head.  Both were self-conscious to a point painful to see.

“It is a pity your first visit should be spoiled by anything so dreadful as the accidental death of this young girl.  It seems to have frightened you both very much.”

“Yes, yes,” muttered the man.  “We never saw anybody hurt before.”

“Did you know the young lady?”

“Oh, no; oh, no!” they both hastened to cry out in a confused jumble, after which the man added: