Hidden (Bone Secrets #1) by Kendra Elliot

Eleven years ago, the Co-Ed Slayer murdered nine female college students on the Oregon State University campus. Lacey Campbell barely survived his attack, but he killed her best friend, Suzanne, whose body was never found.

Now a forensic odontologist analyzing teeth and bones for the state medical examiner, Lacey is devastated when she identifies Suzanne’s remains at a crime scene. She finds comfort in the arms of ex-cop Jack Harper, and sparks fly between them even as a new reign of terror begins. Someone is killing the witnesses who sent the Co-ed Slayer to prison a decade ago. All the evidence points to the Co-ed Slayer as the culprit, only he’s long since dead. So who’s the new killer? And is Lacey next in line to die?