When he had entered the mansion by a private door, Agnes turned and pursued her way along a circuitous path shaded on each side by dark evergreens, and which was the one he had directed her to take so as to regain the front gate of the dwelling. But scarcely had she advanced a dozen paces, when a sudden rustling among the trees alarmed her; and in an instant a female form--tall, majestic, and with a dark veil thrown over her head, stood before her. Agnes uttered a faint shriek: for, although the lady's countenance was concealed by the veil, she had no difficulty in recognizing the stranger who had already terrified her on three previous occasions, and who seemed to haunt her. And, as if to dispel all doubt as to the identity, the majestic lady suddenly tore aside her veil, and disclosed to the trembling, shrinking Agnes, features already too well known. But, if the lightning of those brilliant, burning, black eyes had seemed terrible on former occasions, they were now absolutely blasting, and Agnes fell upon her knees, exclaiming, "Mercy! mercy! how have I offended you?" For a few moments those basilisk-eyes darted forth shafts of fire and flame, and the red lips quivered violently, and the haughty brow contracted menacingly, and Agnes was stupefied, stunned, fascinated, terribly fascinated by that tremendous rage, the vengeance of which seemed ready to explode against her. But only a few moments lasted that dreadful scene; for the lady, whose entire appearance was that of an avenging fiend in the guise of a beauteous woman, suddenly drew a sharp poniard from its sheath in her bodice, and plunged it into the bosom of the hapless Agnes. The victim fell back; but not a shriek--not a sound escaped her lips. The blow was well aimed, the poniard was sharp and went deep, and death followed instantaneously. For nearly a minute did the murderess stand gazing on the corpse--the corpse of one erst so beautiful; and her countenance, gradually relaxing from its stern, implacable expression, assumed an air of deep remorse--of bitter, bitter compunction. But probably yielding to the sudden thought that she must provide for her own safety, the murderess drew forth the dagger from the white bosom in which it was buried: hastily wiped it upon a leaf; returned it to the sheath; and, replacing the veil over her countenance, hurried rapidly away from the scene of her fearful crime. CHAPTER XV. THE SBIRRI--THE ARREST. Scarcely ten minutes had elapsed since the unfortunate Agnes was thus suddenly cut off in the bloom of youth and beauty, when a lieutenant of police, with his guard of sbirri, passed along the road skirting Wagner's garden. They were evidently in search of some malefactor, for, stopping in their course, they began to deliberate on the business which they had in hand. "Which way could he possibly have gone?" cried one, striking the butt-end of his pike heavily upon the ground.