The book is about a suburban family in America, and they are dysfunctional in the usual way. They are parents, a son and a daughter. In the beginning of the book the daughter, the prettiest girl in high school, is spied upon by a boy in her class or school, from a tree. He then falls out, but we don't know what happened to him until the end of the book when it's discovered he was hanged by the cord of the binoculars he was using to Peeping Tom the daughter. It is unclear whether he was killed by the mother who is a witch, or by an alien boy in the girl's class, to protect her virtue.
This was about aliens studying humans, but it's a more a low level kind of "soft sci-fi" like the movie Man on Earth or Primer. I dont remember what the motivations of the aliens was.
This was made into a movie in the 90s perhaps 1985-2005.