“The videos speak for themselves don’t they, and that’s certainly a line of inquiry for us,” New South Wales police commissioner Karen Webb said.

“That’s obvious to me, it’s obvious to detectives, that that seems to be an area of interest – that the offender had focused on women and avoided men,” she told national broadcaster ABC.

Webb stressed that police could not know what was in the mind of the attacker. “That’s why it’s important now that detectives spend so much time interviewing those who know him.”.

Cauchi’s Facebook profile said he came from Toowoomba, near Brisbane, and had attended a local high school and university. A distinctive grey, red and yellow dragon tattoo on his right arm was used to help identify him.

Andrew Cauchi, the father, told local media he was “heartbroken” and did not know what drove his son to kill.

“This is so horrendous, I can’t even explain it,” he told reporters outside his Queensland home. “I made myself a servant to my son when I found out he had a mental illness.”

“I did everything in my power to help my son,” said the visibly distressed father. “I’m sorry, there’s nothing I can do or say to bring back the dead.”

Andrew said he believed his son primarily attacked women because “he wanted a girlfriend, he’s got no social skills and he was frustrated”.

“He is my son, and I am loving a monster. To you he is a monster, to me, he was a very sick boy.”

The other women killed were a designer, a volunteer surf lifesaver, the daughter of an entrepreneur, and a new mother whose wounded nine-month-old baby is in hospital.

The mother, 38-year-old Ashlee Good, handed her injured baby girl to strangers in desperation before being rushed to hospital where she died of her wounds.

Her baby, named Harriet, remains in a stable condition in a Sydney hospital, police said.

Good’s family described her as “a beautiful mother, daughter, sister, partner, friend, all-round outstanding human and so much more”.

“To the two men who held and cared for our baby when Ashlee could not – words cannot express our gratitude”, they said in a statement to Australian media.

The only man killed was 30-year-old Pakistani man Faraz Tahir, who had been working as a security guard when he was stabbed.

A total of eight people wounded in the assault remain in hospital – some in critical condition – after four were released in the past 24 hours, officials said.

Cauchi’s assault, which lasted about half an hour, was brought to an end when solo police inspector Amy Scott shot him dead.

Cauchi is believed to have travelled to Sydney about a month ago and hired a small storage unit in the city, according to police. It contained personal belongings, including a boogie board.

He had been living in a vehicle and hostels, and was only in sporadic contact with his family via text messages, his parents said.

A mound of flowers grew outside the Bondi shopping centre as people paid their respects to the victims.

China student victim talked to fiancé just minutes before deadly Sydney knife attack

Flags across the country flew at half-mast in mourning. The Sydney Opera House is to be lit up with black ribbon in the evening.

Prime Minister Anthony Albanese said he had spoken to the families of some victims.

“The gender break-down is of course concerning – each and every victim here is mourned,” he told ABC radio, promising a “comprehensive” police investigation.

A public coronial inquiry will be held into the attack, New South Wales state premier Chris Minns told reporters.

It will look into the police response and criminal investigation, but also the killer’s past interactions with state health authorities, he said.