Norwegian authorities have chargedwith sexual offences involving some 300 teenage boys -The man, said to be a football referee,, according to Norwegian media.He then convinced the victims to engage in sexual acts - which he filmed - with promises of erotic photos in return, it is claimed.According to the prosecutor's office, about 300 boys, in Norway and other Nordic countries'The case is a serious one, and it is the biggest case of sexual abuse in Norway to date,' state prosecutor Guro Hansson Bull said in a statement.According to the prosecutor's office, about 300 boys aged 13 to 16 were targeted since 2011, in Norway and other Nordic countries., according to reports., but has yet to respond to each individual charge.The trial will be held in 2019.