A man who allegedly killed a woman in Sydney’s central business district before attacking others on a busy city street is expected to be charged with murder on Wednesday.

Officers have been searching Mert Ney’s family home in Marayong in Sydney’s west after Tuesday’s violent rampage, as well as another address at Blacktown.

The 20-year-old, who has spent the night under police guard in hospital, had a history of mental health issues. Overnight he underwent surgery for a cut to his knee.

“It is unclear when he will be deemed medically fit to speak with investigators,” New South Wales police said on Wednesday.

The police commissioner, Mick Fuller, said Ney was expected to be charged with murder as well as serious assault. Police have formed Strike Force Lalchere in response to the stabbings.

The 20-year-old jumped on cars and yelled at bystanders to “shoot me in the fucking head” before being restrained by members of the public – later lauded as “heroes” by police – who used cafe chairs and a milk crate to pin him down.

About an hour after the man’s arrest, the body of a 24-year-old woman with a cut on her neck was found inside an apartment in Clarence Street, in central Sydney. Fuller said Ney had been at the apartment for “business purposes”.

A 41-year-old woman was stabbed in the Hotel CBD, on the corner of Clarence and York streets. She was taken to St Vincent’s hospital suffering a non-life threatening injury from a single stab wound to her back.

Police say Ney did not have any known links to terrorist groups, and that he had acted alone. The attacks are not being treated as a terrorist attack, Fuller said.

The 20-year-old did, however, have “some ideologies in relation to terrorism” and the joint counter-terrorism team would examine if the terrorism threat needs to be reassessed.

“There was certainly information found on him about other crimes of mass casualties and mass deaths around the world,” Fuller said, adding that the material had been discovered on a USB drive.

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Video footage shows Ney, who was armed with a large butcher’s knife, yelling “Allahu Akbar” while wandering the CBD.

The Daily Telegraph reports that he faced a magistrates court in June after being found with knuckledusters. He pleaded guilty to possessing a prohibited weapon and was sentenced to a conditional release order for nine months.

Superintendent Gavin Woodsaid the bystanders who had apprehended the man were “significantly brave people”. “To approach a person with a mindset of obviously what this person [had], with clear evidence of a stabbing previously, these people are heroes.”

He said their actions had prevented others from being hurt. “These members of the public, going about their day-to-day business, have jumped into a situation which was extremely dangerous and hostile and they have brought a person, who we will be alleging has stabbed an innocent person for no specific reason, into custody and allowed us to do our job.”

Scott Morrison characterised the attack as deeply concerning and said his thoughts were with those affected by the incident.

“The attacker is now in police custody following the brave actions of those who were present at the scene and were able to restrain him,” the prime minister said on Twitter.

Police are appealing for witnesses to come forward. In particular they are seeking security surveillance, dashcam and mobile phone footage.


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