Content Warning: This section of the guide references violence, abuse, rape, and homicide.

The book’s narrator, author, and protagonist, Paul Holes possesses many traits that aid the work he does as a criminalist. He is fascinated by science and has a keen intelligence that allows him to understand complex scientific material, such as how DNA functions. Holes is also intellectually stimulated by the puzzle of solving a crime and goes about it in a way that proves effective: He is slow to jump to conclusions and instead carefully gathers all possible evidence, no matter how tedious the task may be. He often thinks unconventionally—a talent that leads him to focus on evidence that others might have overlooked. Further, his passion for his work and his empathy for the survivors of crimes allow Holes to work tirelessly, doggedly following leads until a case is solved. By contrast, Holes conveys that the managerial roles he took on at various points in his career were ill-suited to him—partly because of his lack of people skills and partly because they prevented him from examining cold cases. Over the course of the book, Holes often violates the mandates of his superiors by devoting time and energy to such cases.