Truly Devious: A Mystery

Truly Devious takes place at a boarding school because boarding schools always make good places for books. This rural Vermont school takes the "best", but has no strict admission standards. You just ask to get in, and they decide if you should get in. Attending are a budding novelist, an actor, an engineer and an artist. The protagonist feels a little out of place. Her skill is "solving mysteries". And she is drawn to the school for the unsolved kidnappings and murders from the 1930s. (And it also gets her away from her parents who are employed by a right-wing senator)
The budding actor recruits her and the writer to help write a script for him about the murders. He knows that one of the long-closed tunnels from the incident is now opened. They go down there to film. However, things turn tragic as he dies. Now there is a new murder to solve. She finds a real mystery different, but still uses her skills. In the process she also finds a boy and is really caught with emotions there. (However, her sleuthing ends up causing problems.) She gradually comes of age as she solves the mystery. In the end, the book gives some potential answers, but lives more things untied. This is the first book in a series, rather than a fully standalone book.