Among the tens of thousands of people detained and disappeared in Syria's notorious prison system during the Assad regime, around 700 are thought to have been taken during the Lebanese Civil War. SBS can reveal an Australian citizen is believed to be among those still stuck in a Syrian prison, after he was taken from his family's village in Lebanon. HIs family in Melbourne believe he has been held in Syria for 40 years. This story was produced in collaboration with SBS Arabic reporter Hamssa Abou Kheir.