"The Hypnotist", by Lars Kepler

Book 1, in the Joona Linna series
This novel has a special and interesting story and start with a bang with the brutal murder a family stabbed to death in a Stockholm suburb. The only witness is the critically injured teenager son, Josef Ek who survived the attack and fortunately the older sister was not home at the time and escaped the carnage. The novel is quite intense showcasing graphic images on many occasions.
Dragged into solving this horrific crime is the protagonist, Joona Linna, a deeply damaged Detective who suffers from blinding headaches. Since the boy can barely be questioned in the normal way, Linna calls on Dr. Erik Maria Bark, the Hypnotist. Bark, is also a much damaged man terribly addicted to painkillers he simply eats them like candy. He had sworn to never use hypnosis after a tragic event of the past that is still haunting him. He is reluctantly pressured to hypnotize the boy to obtain details that would help solve the murders and protect his sister who may be running out of time. Don’t be surprised the situation soon spirals of control and we are thrown off by red herrings, many few missteps and definitely in the middle of pretty entertaining stuff.