I did not get the humor some critics mentioned. The story was very disturbing and the book was not particulary well written. It had no descriptive details or language that resonated. Serial murder of innocent people is not funny. The sister killer was a vain and unsympathetic character. While the narrator used the father to justify her actions, it was not believable. It is ironic that the older sister is a nurse. She is supposed to value life yet becomes an accessory to several murders. I get how conflicted she was regarding her sister but her slavish loyalty was over the top