THE SYDNEY KNIFE attacker who killed six people at a shopping centre had suffered mental health issues since he was a teenager, his family said.

Joel Cauchi, 40, from Queensland, had been known to police, particularly over the last five years, but had not been arrested or charged before he committed the attack on Saturday.

Four women and a male shopping centre security guard in his 30s were killed.

In a statement released through Queensland Police, the Cauchi family said: “We are absolutely devastated by the traumatic events that occurred in Sydney yesterday.

“Our thoughts and prayers are with the families and friends of the victims and those still undergoing treatment at this time.

“Joel’s actions were truly horrific, and we are still trying to comprehend what has happened.

“He has battled with mental health issues since he was a teenager.”

Cauchi was identified by New South Wales Police today 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.

His family added: “We are in contact with both the New South Wales Police Force and Queensland Police Service and have no issues with the police officer who shot our son as she was only doing her job to protect others, and we hope she is coping alright.”

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 officers with the investigations.

“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”.

Tributes have been paid to Cauchi’s victims, who included a mother who handed her baby over to strangers after being attacked.

Ashlee Good, 38, died in hospital from her wounds and her nine-month-old daughter Harriet has undergone surgery.

A statement from Ms Good’s family provided to the PA news agency 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.

It added: “We can report that after hours of surgery yesterday our baby is currently doing well.

“To the two men who held and cared for our baby when Ashlee could not – words cannot express our gratitude.”

Dawn Singleton, the 25-year-old daughter of Australian businessman John Singleton, was named as one of the victims by local media.

Two of the victims are from overseas and police are attempting to contact their families.

Slain security guard Faraz Tahir was named and labelled “courageous” by the Australian Pakistani National Association.

And New South Wales Police confirmed a fourth victim was 47-year-old Jade Young, who worked as an architect in Sydney.

The fifth victim of the stabbing spree was identified as 55-year-old Pikria Darchia, New South Wales Police confirmed.

A further 11 people are receiving treatment in hospitals around Sydney for injuries, with 12th person discharged from hospital today.

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.”

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.