Paige Mann, who was married to Mr Roof’s father for 10 years and helped raise him, said that her stepson was so smart that he became bored in school and was a germophobe for some time.
“He went to catechism, he went to church,” Ms Mann said. “He was locked in his room looking up bad stuff on the computer.”
In an interview with the New York Daily News, she said: “Something on the computer drew him in – this is Internet evil. We just thought he was a lazy, this-generation kind of kid.”
Mr Roof’s manifesto, published online, shows how the 21-year-old’s views hardened after the shooting of Travyon Martin in Florida in 2012. Ms Paige claimed that it was only after her step-son began living with his mother over the past few years that he became a recluse.