Cryptogram from Frankenstein; or, the modern prometheus, chapter 7

Six years had elapsed, passed in a dream but for one indelible trace, and I stood in the same place where I had last embraced my father before my departure for Ingolstadt. Beloved and venerable parent! He still remained to me. I gazed on the picture of my mother, which stood over the mantel-piece. It was an historical subject, painted at my father's desire, and represented Caroline Beaufort in an agony of despair, kneeling by the coffin of her dead father. Her garb was rustic, and her cheek pale; but there was an air of dignity and beauty, that hardly permitted the sentiment of pity. Below this picture was a miniature of William; and my tears flowed when I looked upon it. While I was thus engaged, Ernest entered: he had heard me arrive, and hastened to welcome me: "Welcome, my dearest Victor," said he. "Ah! I wish you had come three months ago, and then you would have found us all joyous and delighted. You come to us now to share a misery which nothing can alleviate; yet your presence will, I hope, revive our father, who seems sinking under his misfortune; and your persuasions will induce poor Elizabeth to cease her vain and tormenting self-accusations. - Poor William! he was our darling and our pride!"

The sentence you are solving goes here.

"She most of all," said Ernest, "requires consolation; she accused herself of having caused the death of my brother, and that made her very wretched. But since the murderer has been discovered - "