The Shivering Turn. Sally Spencer

Oxford, 1974. When seventeen-year-old Linda Corbet goes missing, the police dismiss her as an obvious runaway. Only Jennie Redhead, recently driven out of Oxford's police force, is prepared to dig deeper.
She suspects that something truly dark and depraved drove Linda from her beloved home and doting parents. Jennie's investigation leads her to a secret Oxford society and to a clandestine world of violence, excess and desire, hidden behind the city's dreaming spires.