The man who killed six people in a knife attack at a shopping centre in Sydney was known to police, but had not been arrested or charged before he committed the attack on Saturday, police said.

Joel Cauchi, 40, from Queensland, was identified by New South Wales police on Sunday after he was killed by a police officer during the attack at the Westfield shopping centre at Bondi Junction in the east of Sydney.

The lone knifeman attacked shoppers on Saturday afternoon and police said they do not think the attack was motivated by terrorism.

Queensland Police assistant commissioner Roger Lowe told reporters in Brisbane that Cauchi, who he described “itinerant”, had not been “prosecuted or arrested or charge for any offence within Queensland” and said the force was assisting police in New South Wales with investigations.

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A note is left with flower tributes near a crime scene at Bondi Junction in Sydney (Rick Rycroft/AP)

“He has been in contact with the police, primarily in the last four to five years would be the most contact we have had with him. During that contact we are aware that this individual has suffered from mental health,” said Mr Lowe.

Mr Lowe said the attacker’s family has co-operated with police and had sent a message to the New South Wales police “with respect to support the police officer who has killed their son and are expressing their concerns for her welfare”.

Mr Lowe said the family contacted authorities when they saw footage of the attack on television.

New South Wales police are investigating the man, who moved to Sydney a month before the attack, hiring a “very small” storage container in Sydney which police have “worked through”.

Four women and a man in his 30s, a security guard at the shopping centre, died at the scene.

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Karen Webb, police commissioner of New South Wales state, speaks to media at Bondi Junction (Rick Rycroft/AP)

Ashlee Good, 38, died in hospital after being attacked. Her nine-month-old daughter Harriet was injured in the attack and a statement from Ms Good’s family provided to Australian broadcaster ABC said the child is “doing well”.

“Today we are reeling from the terrible loss of Ashlee, a beautiful mother, daughter, sister, partner, friend, all-round outstanding human, and so much more,” the statement said.

The 25-year-old daughter of Australian businessman John Singleton, Dawn, has been named as one of the victims by various media outlets. Two of the victims are from overseas and police are attempting to contact their families.

A further 11 people are receiving treatment in hospitals around Sydney for different injuries. A 12th casualty was discharged from hospital on Sunday.

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Sydney shopping centre stabbing (PA Graphics)

Australian Prime Minister Anthony Albanese hailed the “extraordinary” bravery of people at the shopping centre during the attack.

“We see the footage of ordinary Australians putting themselves in harm’s way in order to help their fellow citizens,” he said. “That bravery was quite extraordinary that we saw yesterday, the best of Australians amidst this extraordinary tragedy.”

New South Wales premier Chris Minns called the attack “horrifying” and praised the efforts of the police inspector who shot Cauchi.

“Sydney has suffered a horrifying and violent attack on innocent people who are doing something everybody does on the weekend and that is going shopping with their family and their friends,” he said.

“Of course, Inspector Amy Scott, who ran towards danger, showed professionalism and bravery and without a shadow of a doubt, saved many, many lives in the last 24 hours.”

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Chris Minns, premier of New South Wales (Rick Rycroft/AP)

Mr Albanese and Mr Minns were among members of the public who laid flowers in Bondi to pay tribute to victims of the attack.The King has said he and the Queen were “utterly shocked and horrified” by the “senseless attack” in Sydney and their “hearts go out to the families and loved ones of those who have been so brutally killed”.

The shopping centre is being investigated by state and federal police and remained closed to the public.