Bitter Moon - Alexandra Sokoloff

FBI agent Matthew Roarke has been on leave, and in seclusion, since the capture of mass killer Cara Lindstrom-the victim turned avenger who preys on predators. Torn between devotion to the law and a powerful attraction to Cara and her lethal brand of justice, Roarke has retreated from both to search his soul. But Cara's escape from custody and a police detective's cryptic challenge soon draw him out of exile-into the California desert and deep into Cara's past-to probe an unsolved murder that could be the key to her long and deadly career.

Following young Cara's trail, Roarke uncovers a horrifying attack on a schoolgirl, the shocking suicide of another, and a human monster stalking Cara's old high school. Separated by sixteen years, crossing paths in the present and past, Roarke and fourteen-year-old Cara must race to find and stop the sadistic sexual predator before more young women are brutalized.