I just finished a really good book. I realized that I especially like chick lit/romance and thriller crossovers. This was one of of those. It was called Big Little Lies by Liane Moriarty. (She's written some other fun novels, including What Alice Forgot and The Husband's Secret.)
The story is set in Australia and focuses on a parent trivia night at a primary school. One of the parents ends up dead. (Nothing to do with a gun.) Then the narrative goes back to the beginning, when the parents met at orientation, and follows the growing tension between them until things explode at the trivia night. (Not literally.) The book had a fun, gossipy vibe and there is a twist when the trivia night finally comes. I recommend it.