Justine Maritz was a simple servent that worked for the Frankenstein family. She had a simple life but was accused for murder. Victor and Elisabeth visited her in prison , they found out she lied on trial. Admitting to the murder of William that she didn't commit. She was scared of being in trouble with the church and going to hell.
So by doing so she could not get out of the crime. She later was hanged. The meaning to this was that Victor didnt stand up for her. He had felt that he commited two murders. He believes that the monster killed his little brother. Victor was depressed and had thought of suicide. These causes that came from the death of Justine Moritz and William would later effect the book.