The Brothers Karamazov is actually an exciting detective and murder mystery. Which of the brothers killed their father? None of them. Which of the brothers killed their father? All of them. Nearly every reader sees himself in this novel and learns that he is both damned and saved. In the process of describing the crime and Dmitry's trial, the novel fully discusses the nihilism and Marxism that has since strangled European civilization. Who would have predicted it? Dostoevsky.
But if he showed us where lay the path to hell, and he was right, at least insofar as Europe was concerned, he also showed us the road to sanctity. He would maintain that the spirit of darkness was proof against smart bombs and directed energy weapons and nuclear weapons of any megatonnage. Those things would be used, to be sure. But the most powerful weapon against the Devil, he maintained, was freedom despite everything, and love despite all.
It sounds like Dostoevsky wasn't really sure if he himself was good or evil. Sort of like Schroedinger's cat: without absolute knowledge, he wasn't good or evil, but half good and half evil. But since absolute knowledge is not possible in this life, these dualities will remain unresolved.