"The Sandman: a Novel" (Knopf), by Lars Kepler
Unlike the creature of myth by the same name, "The Sandman" by Lars Kepler will not put you to sleep. Quite to the contrary, you won't want to put it down. And when you do finally try to go to sleep, you very likely will be afraid to close your eyes.
Written by the wife-and-husband team of Alexandra Coelho Ahndoril and Alexander Ahndoril, who go by the pen name Lars Kepler, "The Sandman" features a serial killer who terrifies even though he is already imprisoned in a maximum security psychiatric facility.
Jurek Walter is serving a life sentence at the beginning of the tale, when a young man, Mikael Kohler-Frost, long thought dead and believed to be one of Walter's victims, reappears, stumbling along a snow-covered railroad bridge, frozen and bloodied. Mikael had gone missing 13 years earlier and was declared dead some half-dozen years later.
Detective Inspector Joona Linna, who captured Walter red-handed as he was forcing an elderly woman into a grave, comes back on the case. Mikael reveals that his sister, Felicia, who was also kidnapped, is likely still alive. And if Walter is in prison, then he must have an accomplice - something Linna suspected when working the original case.
With time running out for Felicia, the police work to locate her and hatch a plan to place an undercover agent, the tough-as-nails Inspector Saga Bauer, posing as a violent patient, into the psychiatric hospital with Walter. It's a risky attempt to reveal details of Walter's crimes and clues to Felicia's whereabouts as Walter is a master of worming his way into his victims' heads.
If Jurek Walter reminds you of Hannibal Lecter, with his ability to impel people to act against their own impulse, you'll be forgiven, as this comparison is made in the book's promotional materials by writer Lee Child. Doctors in the maximum security prison wear earplugs when interacting with Walter so as not to hear his words. As with Jurek Walter's powers of persuasion, I felt impelled by Lars Kepler to finish "The Sandman." The characters got into my head and I couldn't rest until the mystery was revealed.