The Singing Bone by Beth Hahn (2016)

A convicted killer's imminent parole forces a woman to confront the nightmarish past she's spent twenty years escaping.

Alice is a professor in present-day 1999, but when she was a teenager in 1979, she and her friends got involved with a mysterious group headed by the charismatic Jack Wyck. Things ended badly and most of the people involved with Wyck are either in jail or dead. A documentary filmmaker is trying to get in touch with her and other survivors to make a film about the situation and things begin stirring again. 

Very atmospheric, and the story skillfully moves between the time settings. Creepy and good.