1st Case by James Patterson

A computer genius pulls off her greatest hack yet -- and her skill might just get her killed. Angela Hoot's government career begins with an ending. Her unorthodox programming skills get her kicked out of MIT's graduate school and into the Bureau's cyber-forensics unit. A messaging app with sophisticated tracking capabilities surfaces. Its beta users, all young women, are only identified as they turn up dead in their bedrooms. As Angela races to crack the killer's digital code, their technical rivalry escalates. She must deny the killer access to her personal life, or risk losing her life to the underbelly of the Internet.