Singer described the "Apt Pupil"s premise as a "study in cruelty". He prepared for the film by reading books like the 1996 history book "Hitler's Willing Executioners", which confirmed his beliefs that Nazi war criminals felt "guiltless and matter-of-fact about what they did". He referred to how young Todd Bowden's interactions with Nazi war criminal Kurt Dussander start to affect him: "I liked the idea of the infectious nature of evil ... The notion that anybody has the capacity within them to be cruel if motivated properly is, I think, a scary concept." The director also perceived the film as not about the Holocaust, believing that the Nazi war criminal could have been replaced by one of Pol Pot's executioners or a mass murderer from Russia. "It wasn't about fascism or National Socialism. It was about cruelty and the ability to do awful deeds, to live with them and be empowered by them," Singer said. To this end, the director sought to avoid overt use of swastikas and other Nazi symbols. He was also attracted to the film as " idea that the collective awfulness of this terrible thing that happened decades ago in Europe had somehow crept up across the ocean and through time, like a golem, into this beautiful Southern California suburban neighborhood".