[4][5] McNamara was born on April 14, 1970, in Oak Park, Illinois, the youngest child of stay-at-home mother Rita (née Rigney) and trial lawyer Thomas W.

[8] In 1988, she graduated from Oak Park and River Forest High School, where she was editor-in-chief of The Trapeze, the student newspaper, during her senior year.

The documentary also reveals that on September 1, 1992, after having lived in Belfast for a month,[11] McNamara was sexually assaulted by a man she worked for, an incident that would influence her drive to investigate the Golden State Killer.

[2][15] McNamara had a long-standing fascination with true crime originating from the unsolved murder of Kathleen Lombardo that happened two blocks from where she lived when she was young.

[1][9][16] In 2014, McNamara and true crime investigative journalist Billy Jensen were on a SXSW Interactive panel called "Citizen Dicks: Solving Murders With Social Media".

[24][3] Paul Holes, an investigator for the Contra Costa County district attorney's office, stated that McNamara's dogged persistence and trustworthiness with sensitive information about GSK cases earned her an unusual level of cooperation from law enforcement officials.

The manuscript was edited and completed by true crime writers Paul Haynes, Billy Jensen and her widower Patton Oswalt following her death in April 2016.

[30] On the evening of April 24, 2018, authorities in California identified Joseph James DeAngelo as the Golden State Killer and arrested him at his home.

[39][40] According to the autopsy report released online by Radar,[41] her death was due to the effects of multiple prescription drugs including Adderall, fentanyl, and Xanax.