Frankenstein feels he has the right to take the life of his monster because he realizes that he has created a murderer, that the fatality causes that it is against with William, the small brother of Victor, and when knowing of its kinship, in an outburst of rage, it assassinates it.
Then arrange the evidence so that the blame for the murder falls on Justine, the maid responsible for caring for the child.
Following later with more murders like the one of Clerval, in which to Victor is accused to him of this crime, being only saved of the prison and the patíbulo by the intervention of its old father.