The family of five, including three children, were detained on Bali island Tuesday after being deported from Turkey following their arrest on suspicion of planning to cross into Syria and join the jihadists.
The Indonesian finance ministry toda identified the man as Triyono Utomo, an economist who had worked in two different departments at the ministry.
The 39-year-old completed his bachelor's degree in Indonesia and then went to study in Australia, receiving his master's from Flinders University in Adelaide in 2009, the ministry said.
"After that he could no longer be contacted."
The ministry added it would not provide the ex-official with legal assistance.
Police say the former official and his family left Indonesia for Turkey in August and had planned to carry on to Syria.
Hundreds of radicals from Indonesia, the world's most populous Muslim-majority country, have flocked to the Middle East to fight with IS, and authorities have detained a number on their return home.
The emergence of IS has provided a potent new rallying cry for radicals in Indonesia, which has long struggled with Islamic militancy, and sparked fears of a revival of long-defunct extremist networks.
A gun and suicide attack in Jakarta last year, that left four civilians and four assailants dead, was the first major assault claimed by IS in Southeast Asia.
Disclaimer: No Business Standard Journalist was involved in creation of this content
