More than a decade ago, Mr Hadi Masykur was a personal secretary for Para Wijayanto, one of the most wanted terrorists in South-east Asia, and was privy to high-level information about the militant Islamist organisation Jemaah Islamiah (JI).
Today, he preaches about the dangers of extremism that has torn him from his family and sent him to jail.
Mr Hadi joined JI when it was first established in 1993, wanting to help oppressed Muslims. He was then 15.