Sydney knife attacker had mental health issues, ideology not motive, police say

The man who fatally stabbed six people in Sydney had mental health issues in the past and there was no indication ideology was a motive in the attack in one of the city's busiest shopping centres, police said on Sunday.

The attacker, identified by police as 40-year-old Joel Cauchi, was known to police in the neighbouring state of Queensland, and police have spoken to his family after Saturday's attack, according to police from both New South Wales and Queensland.

Cauchi's family recognised 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," said Queensland Police Assistant Commissioner Roger Lowe.

Witnesses described how Cauchi, wearing shorts and an Australian national rugby league jersey, ran through the Westfield Bondi Junction mall with a knife.

He fatally stabbed six people and injured at least 12 before he was shot dead by Inspector Amy Scott, who confronted him solo while he was on the rampage.

Some shoppers and staff at the mall in Sydney's east tried to stop him and crowds sheltered in shuttered shops.

"This was a terrible scene," New South Wales Police Assistant Commissioner Anthony Cooke told reporters.

"There is still to this point, nothing that we have, no information we received, no evidence we have recovered or intelligence that we have gathered that would suggest that this was driven by any particular motivation, ideology or otherwise."

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, said Queenland police officer Lowe. Cauchi had not been arrested or