What is the main conflict in 3rd Degree: A Novel by James Patterson?

This novel takes place in San Francisco, California, in modern times. It follows a serial homicide investigation headed by Lieutenant Lindsay Boxer.

The reader first meets Boxer and her friend Jill, who works for the District Attorney, as they jog through the park. Together with Claire, the medical examiner, and Cindy, a reporter, the women make up the women's murder club that appears in several of James Patterson's novels.