Everything you need to understand or teach I'll Be Gone in the Dark by Michelle McNamara.
Michelle McNamara pieces together evidence involving the elusive Golden State Killer, a serial rapist, burglar, and murderer who terrorized California from 1974 to 1986. McNamara describes the development of her obsession with unsolved cases and the process by which she meticulously compiles evidence about the Golden State Killer. She interviews both amateur sleuths and detectives who have long been on the case, among them Richard Shelby, Larry Pool, and Paul Holes. McNamara narrates several theories about the Golden State Killer's identity and possible motivations, along with a description of detective's procedures in attempting to solve the case, including geographic profiling and the importance of DNA evidence.