Haunting question over Sydney mall stabbings: Why?

What drove Joel Cauchi to murder six people in a busy Sydney shopping center on Saturday?

It is a question investigators are asking as they piece together the events leading up to Cauchi's killing rampage inside the Westfield shopping mall.

As night fell on Sunday, a group of about 40 people from a local Muslim association placed flowers on the ever-growing pile outside the shopping center in the city's Bondi Junction neighborhood, which is usually humming with shoppers.

Australians, largely unaccustomed to violent crime, are still coming to terms with the attack that shattered Sydney as detectives continue to process the crime scene and make sense of the horrific event.

Five women and one male security guard were killed in the attack as Cauchi roved through the packed mall with a large knife. Pictures on social media showed frightened shoppers fleeing the mall or hiding behind shuttered stores.

The Chinese Consulate-General in Sydney said on Sunday that one Chinese national was killed during the attack, and another is among the injured. It said it was deeply saddened by the tragedy and offered condolences to the families of the victims.

Cauchi was tracked down and shot dead by solo senior police officer Amy Scott, who was hailed by Prime Minister Anthony Albanese as a "hero" who had saved countless lives.

One of the dead women was osteopath Ashlee Good, 38, who died at St. Vincent's Hospital on Saturday night from wounds she received trying to protect her 9-month-old baby, who was in a serious but stable condition.

Faraz Tahir, a 30-year-old security guard at the mall who was the sole man killed, arrived in the country last year as a refugee from Pakistan, according to a statement from the Ahmadiyya Muslim Community of Australia, to which he belonged.

Police have described Cauchi, 40, as an itinerant who moved to Sydney, the capital of New South Wales, from neighboring Queensland a month ago.

Queensland Police Assistant Commissioner Roger Lowe told a news briefing on Sunday that Cauchi had never been arrested or charged with any crimes in Queensland, but had been "street-checked "on Queensland's Gold Coast in December, describing the process as "intelligence gathering".

Cauchi had never been found in possession of knives, he said.

Cauchi's family recognized him and contacted police on Saturday after seeing news reports of the killings.

"The family, when they viewed footage of the event on TV, thought that may well have been their son and they reached out to authorities," Lowe said.

Mental health issues

Cauchi had been diagnosed with mental health issues when he was 17 and had been in contact with police frequently in the past four to five years, Lowe said, but police had no indication about why he may have become violent.

His parents issued a statement through police, offering condolences to their son's victims and their families. They also sent a message of "support" to the officer who shot him dead, "expressing their concerns for her welfare".

They said their son had been living in a vehicle and hostels of late, and was only in sporadic contact via text messages.

New South Wales police Assistant Commissioner Anthony Cooke said there was no evidence to suggest Cauchi was "driven by any particular motivation, ideology or otherwise".

"We are continuing to work through the profiling of the offender, but very clearly to us at this stage it would appear that this is related to the mental health of the individual involved," Cooke said.

Britain's King Charles, who is Australia's head of state, posted on the royal family's X account: "Our hearts go out to the families and loved ones of those who have been so brutally killed during such a senseless attack."

Albanese said he had received condolence messages from all over the world, adding the attack highlighted the bravery of ordinary citizens.

Agencies contributed to this story.