In footage shot after his arrest, Mr Ney can be seen lying down in the paddy wagon shouting "God is the greatest" and "He will protect me". He's then seen peering through a small window and speaking to onlookers. Loading Replay Replay video Play video Play video He also had in his possession a phone and USB stick with information about recent mass deaths and white supremacist attacks in the US and New Zealand. Police said the 20-year-old from western Sydney was most likely a troubled man, with a long history of mental health issues and no known links to any terror organisations.

Mr Ney, from Marayong in Sydney's west, allegedly left one woman dead and another in hospital with stab wounds after Tuesday's violent episode, which police say was likely to be related to his "well-known" mental health issues. What we know so far Mert Ney, 20, was seen wielding a knife near the corner of Clarence and King streets about 2pm.

Bystanders restrained him with chairs and a milk crate.

One woman, 24, was killed in a Clarence Street unit. Police discovered her body about 3.15pm.

Another woman, 41, was stabbed in the back at Hotel CBD. She is in a stable condition.

Police say Mr Ney was a "lone actor" with a history of mental health issues and no apparent links to terrorist organisations.

At the time of the stabbings, Mr Ney was on conditional release after pleading guilty to possessing a prohibited weapon in June. In what was described as six minutes "of terrifying carnage", Mr Ney reached the corner of Clarence and King streets, jumping on the roof of a parked car while covered in blood and wielding a bloody butcher's knife. A 41-year-old woman was allegedly stabbed in the back as she walked along the footpath. About 30 minutes later a 24-year-old woman, believed to be a sex worker, was found dead in a nearby apartment block, an incident now linked to the violent episode.

As Mr Ney wielded the knife, many ran in the opposite direction but at least three young men – described by the Police Commissioner Mick Fuller as "highest order heroes" – ran towards him and "effectively arrested" him on the ground alongside other members of the public until police arrived. While his screams suggested a possible allegiance to Islamic extremist ideology, police have since seized a phone and USB stick containing information about recent violent acts of white supremacy in the US and New Zealand. Mr Fuller said the investigation was in its infancy but he was steadfast in saying the "lone actor’s" alleged attack was not currently considered a terrorist incident. "Information found on him would suggest he had some ideologies in relation to terrorism, but he has no links to terrorism. There is no current intelligence on him and he has no other apparent links to other terrorist organisations."

He said if he "had to make a call" he would say "all evidence points" to a mentally unwell man, who it is understood recently absconded from a mental health facility. "He was known to police but his history was unremarkable, compared to the gravity of the crimes he committed," Mr Fuller said. Mert Ney is arrested after being detained by members of public. "He does have a history of mental health … no doubt in coming days investigators will be looking at not just the last couple of days, but the last six to 12 months of his life." Following his arrest, Mr Ney was initially taken to Day Street police station, then to Royal Prince Alfred Hospital, where he underwent surgery for a laceration to his knee.

Loading He remains under police guard in hospital and is continuing to undergo treatment, police said in a statement on Wednesday morning. No charges have been laid, and it is unclear when Mr Ney will be deemed medically fit to speak with investigators, the statement said. Police on Tuesday praised bystanders who gave chase to Mr Ney and tackled him to the ground, restraining him with chairs and a milk crate before police arrived. "The response by members of the community ... was first-rate. Unfortunately, we have lost the life of an innocent person. We will leave no stone unturned," Mr Fuller said.

In London, NSW Premier Gladys Berejiklian said she had spoken to the Police Commissioner and the Police Minister and would be kept updated. "Our thoughts and prayers are obviously with the deceased and the victims of this horrific time," Ms Berejiklian said. The woman who was stabbed outside Hotel CBD is taken away in an ambulance. Credit:AAP "I also want to acknowledge the very brave passers-by who obviously tried to intervene and our thoughts are with the victims and everyone who witnessed this horrific incident." Mr Fuller said the overwhelming amount of news and citizen video footage of the incident would be helpful but it would be Mr Ney’s background over the past year that investigators would be looking at most closely.

"It’s where he has been in the last 12 months, it’s what has influenced him to go from an individual who was living with his parents and seemingly getting on with his life, and turning into someone who was capable of such horrendous crimes." Police outside the Clarence Street apartment where the woman was found dead. Credit:Dean Sewell Police on Tuesday night were at Mr Ney’s house in Marayong, where he lived with his family. Reem Elomair, a neighbour who attended Marayong Public School with Mr Ney, described the 20-year-old as a quiet figure. "He was not much of a talker. We all used to play with his sister in front of the house, and he would come past and watch," she said. "He wouldn’t stop and talk, he would just walk past."

The 24-year-old woman was found in a residential apartment in Clarence Street. Police confirmed the man had previously been at the apartment for a "business purpose". Late on Tuesday night, the woman's body was removed from the building, as police continued to examine the crime scene. The 24-year-old woman's body was taken away from the Clarence Street apartment late on Tuesday night. Credit:Dean Sewell Prime Minister Scott Morrison said the attack was "deeply concerning". "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," he said via Twitter.