"The morning of February 17, I put a wire on my son, and I sent him to school," Chaifetz says in a video he created to showcase the audio clips. "What I heard on that audio was so disgusting, vile, and just an absolute disrespect and bullying of my son, that happened not by other children, but by his teacher, and the aides -- the people who were supposed to protect him. They were literally making my son's life a living hell."

A Queensland primary school principal is threatening to expel students aged under 13 who refuse to delete their Facebook accounts, in a bold bid to stamp out cyber bullying at her school.

The policy has been applauded by cyber safety experts who say schools are grappling to deal with a surge in problems caused when children use social media sites designed for adults.