Riddle (2013) on Netflix

Plot summary

Holly Teller and her younger brother Nathan grow up in a small Pennsylvania town, where Nathan is bullied at school. One day the bullies take him for a car ride, and though he slips away from them, he is never seen again. Three years later Holly, now a college student, comes to Riddle, Pennsylvania, asking questions about what became of him. The sheriff and a town elder want her to drop it, and the town is not inclined to help her. Holly keeps looking, and her search points toward an abandoned psychiatric hospital just outside town, tied to a past the town would rather keep hidden.