Evil, I recounts real homicide investigations of the most horrific serial murderers. The storytelling techniques of Evil, I rely on the most visceral primary source there is: the killer, himself. Each episode possesses its own well-defined voice, chosen carefully to match the real killer's vocal characteristics as heard in court recordings, interviews, and other audio samples. Episodes additionally feature emotional interviews with tragic family members and keen insight from the detectives who cracked the case, but it is the fictionalized first-person narration from the killer's perspective that provides a menacing new look at criminals whose twisted thoughts make one's skin crawl.