The Hypnotist (Joona Linna, Bk. 1)

In the frigid clime of Tumba, Sweden, a gruesome triple homicide attracts the interest of Detective Inspector Joona Linna, who demands to investigate the murders. The killer is still at large, and there's only one surviving witness - the boy whose family was killed before his eyes. Whoever committed the crimes wanted this boy to die: he's suffered more than one hundred knife wounds and lapsed into a state of shock.

Desperate for information, Linna sees only one option: hypnotism. He enlists Dr. Erik Maria Bark to mesmerize the boy, hoping to discover the killer through his eyes. It's the sort of work that Bark has sworn he would never do again - ethically dubious and psychically scarring. When he breaks his promise and hypnotizes the victim, a long and terrifying chain of events begins to unfurl.