Dark Places (2015)

Libby Day survived the massacre of her family in their farmhouse in the Kansas countryside when she was eight, and has been existing on donations and lectures ever since. 30 years ago, the police believed that a satanic cult was responsible for the murder of her mother and two sisters, and her brother Ben was convicted with her testimony in court. However, when acquaintance Lyle Wirth invites Libby to visit "The Kill Club", where amateurs investigate famous crimes, she finds that they believe Ben is innocent. Libby needs money, so she accepts to revisit the slaughter of her family, and she faces up to the painful revelations and the ultimate truth.