The lava witch / Debra Bokur.

In a remote, mountainous area of a Maui forest near Haleakala volcano, the naked body of a young woman is found hanging from a tree. The devil is in the details: the woman's nostrils, mouth, and lungs are packed with lava sand. Her hands are bound in twine. Her feet are charred and blackened, suggesting a fire-walking ceremony. Detective Kali Māhoe's suspicions are immediately aroused. It has all the signs of a ritual torture and murder. But Kali's investigation soon leads her down a winding trail of seemingly unconnected clues and diverging paths--from the hanging tree itself, a rare rainbow eucalyptus, to rumors of a witch haunting the high areas of the forest, to the legend of the ancient Hawaiian sorceress Pahulu, goddess of nightmares. Casting a shadow over it all--the possibility of a Sitting God, a spirit said to invade and possess the soul.