Mindhunter: the possibility of knowing evil

In the first episode of the Netflix series Mindhunter (2017-), two protago­nists discuss the possibility of understanding people who murder compulsively and repeatedly. They are Holden Ford (Jonathan Groff) and Bill Tench (Holt McCallany), FBI officers about to embark upon a long-term study of the psy­chology of serial killers. Tench has a word of warning:
Tench: Let me tell you something about aberrant behaviour Holden, it's fucking aberrant. If we understood it, we'd be aberrant too. Fortunately, it is not incumbent upon us to write a dissertation.
Ford: Well, maybe we should.

What does it take to understand evil? How does one hunt a mind that is broken in a seemingly inaccessible way? What would it be to capture such a mind and what are the moral hazards of such a venture? The questions are posed in a clear and forthright way in the first series of Mindhunter (they mostly disappear from view in the second series). Over ten episodes, the first series draws out the epistemological struggle of its protagonists and gives it both structure and depth. There are three protagonists: Tench and Ford are soon joined by a civil­ian psychologist, Wendy Carr (Anna Torv}, and they each represent a different epistemological position. The conflict between them dramatises the philosophi­cal question of the possibility of knowing evil.