The Grapes of Wrath is about money, wine, and murder!
I think you are correct
Murder and suspects is a very common theme within popular books.
Yes murder and suspect are main subject 
whats your favorite genre of books?
I like to read romance theme books
Written by Tracey Graves, The Girl He Used to Know is one of top rated romance books of 2021.
I am thinking to buy that romance book
The book follows an incident regarding the bullying of a girl in seventh grade.
That means you have read this book