I think that the boys themselves are responsible for the DVD but there may have been some media influence like video games and TV shows. Maybe their parents didn’t teach them wrong from right but this is highly unlikely. Maybe they are just sick in the head. Or maybe they just didn’t think before they acted and made a stupid mistake. AlthoughI”m not saying this justifies what they did, it was sick and wrong. But they obviously need help and they should apologose to the girl and make amends. It is SO wrong what they did but everyone deserves a second chance.