'I'll Be Gone In The Dark' HBO Preview: Michelle McNamara's Work Explored In True Crime Series

On June 28, "I'll Be Gone in the Dark" will premiere on HBO. The six-part true-crime series will follow Michelle McNamara's investigative work as she attempted to identify the Golden State Killer prior to her sudden death in 2016. Here's what you need to know about the new docu-series before its premieres.

The upcoming HBO program is based on McNamara's 2018 book, "I'll Be Gone in the Dark: One Woman's Obsessive Search for the Golden State Killer." Throughout the work, McNamara who previously created the website TrueCrimeDiary.com and appeared on "48 Hours," offered readers "a chilling account of a criminal mastermind and the wreckage he left behind."

As stated by the Barnes & Noble listing for "I'll Be Gone in the Dark," the journalist "pored over police reports, interviewed victims, and embedded herself in the online communities that were as obsessed with the case as she was" to create the book. The project was then released posthumously before being turned into the upcoming HBO series.

As seen in the preview below, comedian Patton Oswalt, who was once married to McNamara, revealed that during her efforts, she "would actually go to a crime scene and walk a case." After following the leads herself, she then reached out to those who were conducting their own investigations and was introduced to new details.

As for what fans can expect to see when they tune in to watch "I'll Be Gone in the Dark," the story will be told using McNamara’s own words. A combination of "exclusive original recordings and excerpts from her book read by actor Amy Ryan" will be paired with "extensive archival footage and police files as well as exclusive new interviews with detectives, survivors and family members of the killer" in order to create a more complete picture of what transpired.

This, says HBO, will weave together "a picture of a complex and flawed investigation that challenged police for decades." Those who tune in on June 28 will get to learn how the case was solved and how a defendant was ultimately brought forth after years of hiding.

"I'll Be Gone in the Dark" premieres Sunday, June 28, at 10 p.m. EDT on HBO GO and HBO NOW​.