Queenslander Joel Cauchi, 40, stabbed six people to death and seriously wounded 12 others in a killing spree at Westfield Bondi Junction on Saturday afternoon.
He was shot dead by Inspector Amy Scott, with NSW Police confirming there is no evidence to suggest his attack was driven by any motivation or ideology.
"At this stage it will appear related to the mental health of the individual," NSW Police Assistant Commissioner Anthony Cooke told reporters on Sunday.
Cauchi moved to Sydney from Queensland in March and rented a small storage unit.
Queensland Police Assistant Commissioner Roger Lowe said Cauchi had been diagnosed with mental illness at 17 and, based on its investigations, his condition had declined in the last few years.
"He has been in contact with the police primarily in the last four to five years would be the most contact we've had with them."
Cauchi had no record of being subject to a domestic violence order, despite most of his victims being women.
Queensland police have had no contact with Cauchi since December, when he was street checked on the Gold Coast.
Cauchi's family, with whom he only made periodic contact, reached out to authorities after seeing his image on TV and is helping police.
It is believed he was sleeping in a car and backpack hotels.
"Our understanding from speaking to the family (is) he has been an itinerant," Mr Lowe said.
CCTV footage in the hours before the attack showed Cauchi, wearing a black backpack, ordering a meal from a Vietnamese restaurant on Oxford Street.
"Let me gently massage all of your body," the now-deleted profile read.
Google reviews under the name Joel Cauchi suggest he also frequented a brothel and strip clubs across NSW and Queensland.
His now-deleted Facebook profile stated he grew up in Toowoomba, and studied at Harristown State High School and the University of Southern Queensland.
In a post from his account to a Facebook group in December 2020, Cauchi was looking to meet up with "groups of people who shoot guns, including handguns".
"Please send me a DM (direct message) if you can help me out! I live in Brisbane by the way," he wrote.
Cauchi's social media profile indicated he worked as an online English tutor and he notified another Facebook group of plans to go surfing at Bondi six days before the attack.
By Callum Godde
