What evidence suggests Victor feels responsible for the murder? What evidence illustrates that he still blames the creature?

Which murder are you referring to?

His brothers

In Chapter Eight, we come to see that though we might be tempted to hold Victor responsible for the verdict (Justine's trial), this is an overly simplistic view of events. Frankenstein's decision to conceal the truth is terribly misguided; Shelley, however, gives us no indication that he does this in order to absolve himself of guilt. "Fangs of remorse" tear at him, and, in his own heart at least, he bears the guilt for both William's murder and Justine's execution. He can share his terrible secret with no one, and is thus utterly isolated, an outcast from human society.