Fever Of The Bone by Val McDermid

A forensic psychologist, Tony Hill, and his long-time ally, Detective Carol Jordan, race to stop a ruthless killer who preys on vulnerable young women via anonymous online communities; as their profile of the perpetrator grows, the investigation exposes a dark web of cyberbullying, local secrets and personal wounds, forcing both investigators to confront past traumas and the moral costs of justice in a connected age.

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