When Anders Breivik opened fire on Utoya Island in 2011 he commited the worst massacre in Norway's history, killing 69 people, many of them teenagers. He had, earlier that day, taken 8 lives in the bombing of a Government building in Oslo. During his trial the world debated whether he was insane or pure evil. We talk to people who met and knew him, as well as survivors of his murderous spree.