Detective Chief Inspector Tony Brown said: “Throughout this difficult case, the school, the local authority, the families involved and the wider Welsh language community have supported not only each other but also our investigation for which we are very grateful.
“Nobody could have foreseen that this kind of offending would take place.
“Since Williams was arrested on January 23 we have identified, traced and spoken to 92 young people or their parents.
“This would not have been possible without the full co-operation of the school, the council, and also Gareth Williams’ family. Their help enabled us to quickly identify victims and offer them appropriate support services.
“All material and equipment has been fully examined by a team of highly-skilled individuals from our high-tech crime unit and today’s sentencing concludes what has been a very distressing investigation.
“We hope the decision of the court will now allow all families concerned, and the school, to come to terms with what has happened and begin to put this distressing episode behind them.”