Bitter Moon (The Huntress/FBI Thrillers #4)

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.