In Volume I, chapter 6 of Mary Shelley's novel Frankenstein we find that the creature avenges itself one more time against Victor by directly attacking his younger brother, William.
William, the other brother Ernest, and their parents are walking the shore by the time that Ernest and William remain behind to play. William wants to hide from Ernest, but is never to be found again. When Ernest comes to his parents, they spend the night and then all of the next day looking for William. William's nanny, Justine, is nowhere near because she had taken time off. Hence, she is not able to help the child. The body of William is found the next morning, clearly murdered in a brutal way. We know that Justine reacts in such a violently hysterical way that she becomes ill for several days.
He then related that, the morning on which the murder of poor William had been discovered, Justine had been taken ill, and confined to her bed for several days. During this interval, one of the servants, happening to examine the apparel she had worn on the night of the murder, had discovered in her pocket the picture of my mother, which had been judged to be the temptation of the murderer.