A total of 15 innocent people are dead after Naveed Akram, 24, and his father Sajid Akram, 50, used long-range firearms to shoot Jewish festival-goers at Sydney's Bondi Beach on Sunday night.
Sajid, a licensed gun owner, died at the scene following a shootout with police, and Naveed remains in hospital under police guard with critical injuries.
Naveed is an Australian-born citizen whose father arrived in Australia in 1998 on a student visa.
The elder Akram transferred in 2001 to a partner visa and has been on resident return visas after making three overseas trips since then, Home Affairs Minister Tony Burke told reporters on Monday.
Prime Minister Anthony Albanese confirmed Naveed had come to the attention of domestic spy agency ASIO in October 2019.
"He was examined on the basis of being associated with others, and the assessment was made that there was no indication of any ongoing threat or threat of him engaging in violence," he told reporters.
The shooters had been staying at an Airbnb in Campsie, about half an hour from the family home of Bonnyrigg in southwest Sydney where several forensic investigators were inspecting the home on Monday.
Wearing a cap emblazoned with the Australian flag, a man who said his name is Stuart parked outside the red brick home of the gunmen with a white Toyota Prius parked in the driveway.
"I came to this country when I was 14 ... it's distressing that our neighbour is a terrorist. What do you want me to say?" he shouted in an expletive-ridden tirade to reporters as his wife shed tears.
Sanaa Shooka, a Chaldean Christian who fled Iraq to Australia as a refugee, said the trauma of seeing the carnage at Bondi immediately transported her to darker days.
"We left Iraq because of these terrorist acts. We came here from Baghdad escaping ISIS in 2014 after they came to power," she told AAP on Monday, referring to the terrorist group that took over large tracts of Iraq and Syria.
"We expected safety here but it seems like ISIS have spread everywhere."
Her cousin Iman Shooka, 46, who did not know the offender's family but lives across from the street from them, said the attacks on civilians were painful reminders that terrorist attacks could happen anywhere.
"We are feeling deep disgust because it reminds us of years of fear and being under siege as a minority," she said.
Naveed is expected to survive his injuries as investigators prepare to lay charges against him.
