McNamara passes away in her sleep on April 21, 2016, leaving I’ll Be Gone in the Dark unfinished. Journalist Billy Jensen and researcher Paul Haynes, a prominent member of the GSK crime forum (who McNamara calls the “Kid”), continue McNamara’s work. Haynes and Jensen write Part 3 of the book, describing McNamara’s research methods and the avenues for further investigation into the GSK.

McNamara amassed thousands of files relating to the GSK during her research, and was in the process of systematically going through the information at the time of her death. McNamara’s notes are extensive, ranging from collections of maps of the neighborhoods where the GSK struck, to lists of items the GSK stole from his victims. Haynes and Jensen note that McNamara was particularly invested in a form of investigation known as geo-profiling.

In geo-profiling, investigators use the locations of a serial killer’s crimes to deduce where the killer lives. Haynes and Jensen write that, given the GSK’s continual attacks in the Sacramento area, it is almost a certainty that the GSK lived in Sacramento in the late 1970s. They also argue that it is likely the GSK lived in Southern California during the early 1980s, when he committed a series of double homicides.