His mother said that her son had lived at home until he was 35, at which point he had been doing well and wound back his medication before he moved to Brisbane and stopped seeing his regular doctor.
During a visit home in January 2023, he clashed with his father over his collection of US Army combat knives.
“I said, ‘Joel, you can stay here as long as you like, but you are not going to have these in my house’, and so I took them off him, knowing that there was going to be pandemonium, but I was willing to put up with it,” the father said. “He rang the police saying I stole his knives.”
Cauchi travelled to NSW last month, where police said he was sleeping rough.
Six days before the attack, he posted in a Facebook group looking for surfing buddies.
In 2020, he posted that he was looking “for groups of people who shoot guns, including hand guns, to meet up with, chat with and get to know” in an outdoor adventure group.
Cauchi had reportedly been making searches “about killing” on his phone prior to the attack.
Previously, he had uploaded a profile to an escort website as well as dating apps.
“He was a lovely guy when I met him, definitely quiet and reserved,” a woman, who wished to remain anonymous, told Daily Mail of their date in April 2020. “I’m just very shocked at what has happened.”
When asked if he thought his son had targeted women during the rampage, Cauchi’s father responded: “He wanted a girlfriend and he’s got no social skills and he was frustrated out of his brain.”
Cauchi’s mother, Michele, added, “This is a parent’s absolute nightmare, when they have a child with a mental illness, that something like this would happen. If he was in his right mind, he would be absolutely devastated at what he has done.”
If you or someone you know needs help, contact Lifeline on 13 11 14 or lifeline.org.au