Five women and one man were murdered in the stabbing on Saturday at Bondi Junction Westfield. Seven victims remain in hospital, including an infant girl, whose condition has improved from critical to serious.

The killer, 40-year-old Queensland man Joel Cauchi, seemingly singled out women in the nation’s worst massacre in recent years. He was shot dead by police at the scene.

NSW Commissioner Karen Webb said late on Monday NSW police would go to Queensland to talk to Cauchi’s family, associates and friends to “give us an insight into the offender and what he might have been thinking”.

“He had a fascination with knives, we’ve been told that. What else was on his mind we really don’t know,” she said of Cauchi, who moved to Sydney from Queensland in March.

As a floral tribute to the victims grew at Bondi Junction, Premier Chris Minns said a special coronial inquiry would examine the circumstances of Cauchi’s “horrifying, vile act”.

The inquiry, bolstered by up to $18 million in extra funding, would look at the police response, as well as the killer’s interactions with NSW and Queensland agencies.

Mr Minns said the killer’s motive might never be known, but that it was “the truth of the matter” that many women were targeted in the attack, which could pave the way for security guards in shopping centres to be armed.

The killer’s father Andrew Cauchi said his son, with whom he had periodic contact, battled mental health issues, such as schizophrenia, for decades.

“I’m loving a monster. To you he’s a monster but to me he was a very sick boy,” Mr Cauchi said outside his home in the regional Queensland city of Toowoomba.

“This is so horrendous I can’t even explain it. I’m just devastated, I love my son.”

Hundreds of people were forced to flee the east Sydney shopping centre during the attack that claimed the life of 38-year-old osteopath Ashlee Good and Dawn Singleton, 25, the daughter of high-profile businessman John Singleton.

Architect Jade Young, 47, artist and designer Pikria Darchia, 55, and 27-year-old Chinese student Yixuan Cheng were also murdered.

Security guard Faraz Tahir, 30, a Pakistani refugee, was the only man killed.

The terrifying afternoon attack, vision of which was widely circulated on social media, has led to an outpouring of grief in the state where such killings are rare.

Prime Minister Anthony Albanese, who laid flowers at the scene with Mr Minns on Sunday, said it was a difficult time as the nation grieved.

“At the same time, there are extraordinary acts of heroism that we applaud,” Mr Albanese said.

Authorities have praised the bravery of the police inspector who shot Cauchi dead as well several shoppers who confronted him during the ordeal.

Since the attack, official flags have flown at half mast and the Sydney Opera House sails were lit with a black ribbon on Monday night.

A permanent memorial is being considered for near the Bondi shopping centre site.

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