During his 14 years in Australia after migrating from Singapore, Zulfikar Mohamad Shariff became known as an outspoken and occasionally controversial figure who promoted Muslim causes, such as halal exports and Islamic finance, before falling out with some local community leaders.
Two of his friends interviewed by The Sunday Times expressed surprise at his detention in Singapore on terror-related charges earlier this month.
On Friday, Singapore's Ministry of Home Affairs (MHA) said that Zulfikar, 44, a Singaporean who also took up Australian citizenship, had been detained under the Internal Security Act. He was arrested on July 1 when he returned to Singapore for a visit.
The ministry said he had actively spread radical ideology online, incited violence and radicalised at least two Singaporeans. It said he had made many Facebook posts that promoted and glorified terror group Islamic State in Iraq and Syria (ISIS) and its violent actions.
The detention made headlines in Australia yesterday.
The authorities in Australia have not commented on the case or on whether they were involved in any investigation into Zulfikar.
"The Australian government is aware of the Singaporean Government's press statement that Mohamad Shariff Zulfikar has been arrested in Singapore for terrorism-related activities," a spokesman for Australia's Department of Foreign Affairs and Trade told The Sunday Times last night.
"Consular officials are seeking to provide assistance to Mr Mohamad Shariff. However, Singapore does not recognise dual nationality, and Mr Mohamad Shariff is being treated as a Singaporean citizen. For privacy reasons, no further comment will be provided on this case."
The Australian Federal Police would not comment yesterday on whether it had investigated Zulfikar or had any involvement in his arrest in Singapore.
"We don't comment on individuals," a spokesman said.
A close friend in Melbourne, who did not want to be named, said Zulfikar recently claimed that he did not believe he would face trouble if he returned to Singapore.
The friend said Zulfikar "has strong views and that may put people off". "It is a bit of a shock," said the friend, who is active in the Muslim community, of the arrest.
After leaving Singapore for Australia, Zulfikar spent his initial years in Melbourne as a researcher at Monash University before working at a business promoting halal products. He helped to organise a conference in Melbourne in 2007 to promote efforts to encourage Australian halal exports across the region, giving numerous interviews on the topic to local media.
He also worked in Islamic finance, doing sales and marketing from 2004 to 2006 for the Muslim Community Cooperative of Australia. He is well known in the Muslim community in Victoria state, where there are about 150,000 Muslims, who make up some 3 per cent of the population. The close friend said: "He has been under the radar (in Melbourne) for the last four or five years. He had some personality clashes with community leaders."
In recent years, there have been numerous terror attacks and alleged plots in the state capital Melbourne, as well as in Sydney, mainly involving radicalised teenagers.
MHA said Zulfikar embarked on the path of radicalism as early as 2001 and joined hardline group Hizbut Tahrir in Australia. The global organisation, founded in Jerusalem in 1953, seeks to replace the system of nation-states with a caliphate.
In recent years, Zulfikar has been completing a PhD in international relations at La Trobe University in Melbourne and is believed to have been in his final year of studies.