For more than 10 years, a mysterious and violent predator committed 50 sexual assaults in Northern California before moving south, where he perpetrated 10 sadistic murders. Then he disappeared, eluding capture by multiple police forces and some of the best detectives in the area. Three decades later, Michelle McNamara, a true crime journalist who created the popular website TrueCrimeDiary.com, was determined to find the violent psychopath she called "the Golden State Killer." Michelle pored over police reports, interviewed victims, and embedded herself in the online communities that were as obsessed with the case as she was.