When he first settled in Australia in 2002, Zulfikar bin Mohamad Shariff was known as a social activist fighting for the right of Singapore's schoolgirls to wear the Islamic headscarf.

In an interview with The Age, the newly-arrived Zulfikar was enthusiastic about his new home. "In Australia you can think independently and speak freely. You don't have that in Singapore," he said.

But when the 44-year-old Australian resident returned to Singapore this month, he was arrested for "terrorism-related activities", which included supporting Islamic State through Facebook posts. It is now alleged that during more than a decade in suburban Melbourne the Singapore-Australian dual national became increasingly radicalised.

After holding him this month under the Internal Security Act (ISA), the Singapore Government ordered Zulfikar be jailed for two years.