Westfield Bondi Junction remained closed on Sunday as police combed the sprawling crime scene,piecing together the final movements of Cauchi,whose killing spree – with what onlookers described as a 30cm hunting knife – ended when he was shot by NSW Police Inspector Amy Scott.

Scott was hailed as a hero on Sunday,both by those who witnessed her courage and by the state’s leaders. She “ran towards danger,” said Minns,and “without a shadow of a doubt,saved many,many lives … the best in this state confronted one of the worst acts we’ve ever seen.”

Two French construction workers at the shops on a Saturday afternoon have become unlikely heroes after they werefilmed attempting to stop Cauchi’s murderous rampage.

Damien Guerot and Silas Despreaux are both French construction workers employed by a small building firm on the north shore. Footage shows Guerot standing at the top of an escalator brandishing a bollard as Cauchi advances,and the two were later seen sprinting after Scott towards Cauchi. “I didn’t know the situation,I didn’t know who he was,I just saw someone doing something crazy,” Guerot told Seven News.

In a statement,Cauchi’s family – anguish evident as it both mourned for their son,and reviled his actions – said it took no issue with the actions of Scott,who was simply doing her job to protect others. “We hope she is coping alright,” they said.

Investigators say there is no evidence to suggest any ideology behind Queensland-born Cauchi’s killing spree. One line of inquiry is why so many of his victims – five out of the six dead,and most of the injured – were women.

Cauchi was from Toowoomba,west of Brisbane;his parents have lived in the same house in a northern suburb of the city for decades. He was diagnosed with a mental illness when he was 17. Police believe he lived with schizophrenia and used drugs including methamphetamine and psychedelics,and he had been treated by a private psychiatrist since 2012.

“Joel’s actions were truly horrific,and we are still trying to comprehend what has happened,” his family’s statement said. “He has battled with mental health issues since he was a teenager.”

Until recently,Cauchi was drifting around south-east Queensland,living in hostels and his car. He moved to NSW about a month ago for unknown reasons,hired a small storage unit in the inner city – just a square cubic metre of space – for his meagre belongings,including a boogie board,and lived at no fixed address.

A social media trail shows Cauchi asking for surfing buddies on a Bondi Facebook page less than a week ago. He joined pages for singles in NSW and Nudists in Melbourne,and posted fully dressed pictures of himself on an escort page. He was an enthusiastic reviewer,supporting a Toowoomba strip club (“This is a great place,I loved it! The staff and girls were fantastic”) and raving about Palm Beach (“a beautiful place”).

People who have interacted with him found him odd. “Always wandered around talking to himself,definitely some mental health issues,” said one. “He was a weird-looking cat,” said another.

Queensland authorities said Cauchi had never been arrested but he had been in contact with police over the past four to five years and was “street checked” by officers as recently as December on the Gold Coast.

His parents had not heard from him since March,and contacted police when they saw footage of the killer.

NSW Health will station counsellors in Bondi,for anyone who has been distressed by the killings.

With Megan Gorrey,Patrick Begley,Sarah McPhee,Matt O’Sullivan,Clare Sibthorpe,Daniella White,Ben Cubby,Sally Rawsthorne,Perry Duffin,Josefine Ganko,Anthony Segaert,Alexandra Smith and Caitlin Fitzsimmons.

If you or anyone you know needs help,call Lifeline on 13 11 14 (and seelifeline.org.au) or Beyond Blue on1300 22 4636 (and seebeyondblue.org.au).