I’ll Be Gone in the Dark is a true crime book written by Michelle McNamara about the Golden State Killer (GSK). The GSK committed his crimes—a series of rapes escalating to homicides—in Northern and Southern California during the 1970s and 80s. McNamara’s book describes both the GSK’s crimes and her own pursuit of the criminal some 30 years later. The book was published posthumously in 2018, nearly two years after McNamara’s death. 

The narrative describes how the GSK began to commit crimes in the Sacramento area in 1976. Over the course of nearly two years, the GSK breaks into homes and rapes women, earning him the nickname “East Area Rapist.” At first, the GSK targets isolated women, but he soon shifts to targeting straight couples when they are asleep, tying up the man and then raping the woman. The GSK’s assaults are characterized by their careful planning: He often surveils his victims for months before the attack to gather information. The GSK also frequently steal items from his victims, drawn to items that hold sentimental rather than monetary value.

The GSK disappears from Sacramento before resurfacing in San Francisco’s East Bay area in the fall of 1978, continuing his spree of rapes. Detectives are unable to apprehend the GSK, and witnesses offer conflicting descriptions of the GSK’s appearance. In fall 1979, the violence of the GSK’s crimes escalates. He commits a series of brutal murders in Santa Barbara and Orange County in Southern California. The GSK bludgeons his victims to death using large items found at the victims’ homes. At the time of the crimes, detectives fail to realize that a single individual is responsible for the various murders, and the GSK remains at large.

In the 1990s, the Orange County Sherriff’s Department begins investigating cold cases using innovations in DNA technology. Police discover that a single individual is responsible for the string of murders in both Santa Barbara and Orange County in the early 1980s. Several years later, an individual investigating the East Area Rapist, Paul Holes, uses DNA evidence to demonstrate that the same individual committed both the rapes in Northern California and the murders in Southern California. Though detectives now have a DNA profile for the GSK, they are unable to match his DNA with any known felons in the California penal system. These detectives continue their search for the GSK, though they are unable to find any evidence revealing the GSK’s identity.

In Part 2, the book focuses on McNamara’s own investigation into the GSK’s crimes. McNamara is a non-fiction journalist who begins writing a true crime blog in 2006. Her interest in serial killers stems from an event in her childhood: a neighbor was murdered and the killer never found. McNamara becomes obsessed with uncaptured serial killers and begins to use the internet to conduct amateur investigations into unsolved cases from her home. After reading a book about the GSK written by a former detective, McNamara channels her investigative energies into finding this specific killer.

McNamara meets with various detectives investigating the GSK. Paul Holes takes her on a tour of the GSK’s crimes in California’s Contra Costa County, and the two exchange theories as to the killer’s biography. McNamara describes the psychology of both herself and these investigators, writing about how the desire to hunt down the GSK similarly dominates their lives. McNamara describes various times in which she believed she had discovered the GSK, only for DNA evidence to prove that the suspect was not a match. Though these failures leave McNamara bitterly disappointed, her husband, the comedian Patton Oswalt, comforts McNamara and encourages her to keep hunting.

McNamara dies in her sleep, leaving the manuscript of I’ll Be Gone in the Dark unfinished. Two colleagues of McNamara’s, Paul Haynes and Billy Jensen, arrange McNamara’s drafts for publication. Together, they write the book’s Part 3, which describes McNamara’s massive collection of evidence relating to the GSK. At the time of her death, McNamara had been working with investigators to attempt to discover the GSK’s identity through geo-profiling and DNA analysis. The GSK’s identity was still unknown at the time of the book’s publication. However, several months after the publication, federal officers arrested Joseph James DeAngelo for the GSK’s crimes.