Reality isn ' t an issue to the viewer as the vast vast majority cannot conform or relate to the truth or with the scientific psychology or neurology reasoning beyond why what they are seeing isn ' t possible . To the viewer , child abused something something mental trauma abuses children is a perfectly reasonable followthrough of logic for a cereal killer . Put it another way because of its rarity or unrealistic nature , it MAKES the plot horrifyingcompelling and hence retains viewing figures . The Fall is one of the most successful BBC drama ' s . Its insanely good . The fact the boy gets abused and raped for years on end may not be the same for people in real life , its a very compelling storyline and backstorymotive .