Was this the murderer?
This pale, lean servitor, with a tray in his hand on which rested a single glass of water?
Mr.Gryce was so astonished that he looked at Styles for explanation.
But that officer, hiding his own surprise, for he had not expected this peaceful figure, urged him in a whisper to have patience, and both, turning toward the man again, beheld him advance, stop, cast one look at the figure lying on the floor and then let slip the glass with a low cry that at once changed to something like a howl.
"Look at him! Look at him!" urged Styles, in a hurried whisper.

"Watch what he will do now.

You will see a murderer at work." And sure enough, in another instant this strange being, losing all semblance to his former self, entered upon a series of pantomimic actions which to the two men who watched him seemed both to explain and illustrate the crime which had just been enacted there.
With every appearance of passion, he stood contemplating the empty air before him, and then, with one hand held stretched out behind him in a peculiarly cramped position, he plunged with the other toward a table from which he made a feint of snatching something which he no sooner closed his hand upon than he gave a quick side-thrust, still at the empty air, which seemed to quiver in return, so vigorous was his action and so evident his intent.
The reaction following this thrust; the slow unclosing of his hand from an imaginary dagger; the tottering of his body backward; then the moment when with wide open eyes he seemed to contemplate in horror the result of his own deed;--these needed no explanation beyond what was given by his writhing features and trembling body.

Gradually succumbing to the remorse or terror of his own crime, he sank lower and lower, until, though with that one arm still stretched out, he lay in an inert heap on the floor.
"It is what I saw him do upstairs," murmured Styles into the ear of the amazed detective.

"He has evidently been driven insane by his own act." Mr.Gryce made no answer.