But they added they had found no links between him and terrorist organisations

They alleged they found USB stick on him referencing the Christchurch attack

NSW Police have said the suspect 'may have ideologies related to terrorism'

Suspect was later captured by hero bystanders using chairs and a milk crate

At least one person stabbed as alleged attacker Mert Ney, 20, ran through street

Body of woman, 24, later allegedly found with throat slashed in a CBD building

A knife wielding man went on a rampage through Sydney's CBD on Tuesday

A blood-soaked man screaming 'Allahu Akbar' has gone on a rampage with a butcher's knife through central Sydney - allegedly killing a 21-year-old woman inside a unit and stabbing another in the back at a nearby pub.

The dead woman was found inside a King Street apartment, allegedly with her throat slit, after the knifeman was subdued by heroic bystanders about 2pm using chairs and a milk crate in Wynyard Street after he attempted to stab multiple people.

Police are investigating whether the alleged attacker, Mert Ney, 20, from Blacktown in the city's west, had escaped from a mental institution.

They do not believe the incident is terror-related, and said the alleged attacker did not have links to any terrorist organisations - despite witnesses reporting the attacker was muttering religious slogans including 'Allahu Akbar'.

NSW Police Commissioner Mick Fuller said however they found information on the man including a USB stick 'suggesting he had some ideologies related to terrorism'.

A man with a knife (left) can be seen walking towards a bystander (right) who was forced to use a chair to protect himself

The thumb drive allegedly also referenced mass shootings in New Zealand and the USA - including March's Christchurch terror attack.

Commissioner Fuller added the suspect had been known to police, although his prior history did not compare to his alleged actions in the heart of Sydney's CBD.

According to The Daily Telegraph, Ney had a charge dismissed by a magistrate in June.

He was caught with knuckledusters but was dismissed under a Section 10 without conviction in Blacktown Local Court.

Police were called to his family home in Marayong after reports of 'concern for welfare' and seized the weapons.

He had a charge dismissed by a magistrate in June.

He was sentenced to a nine months conditional release order on the condition he didn't commit another offence.

The conditions also outlined that Ney was to seek help for his mental health.

Just last Wednesday, August 7, he attended the emergency room at Blacktown Hospital while suffering from a drug overdose.

The alleged attacker is believed to have acted at random, and is expected to be charged later on Tuesday evening.

Police added a third woman also presented herself to a police station and had her hand wrapped in a scarf, but authorities suspect she may have only been a witness.

Stunned onlookers were scene frozen in the street as the man with a knife began his stabbing rampage through the streets

How the Sydney CBD rampage unfolded 2pm Police receive calls about a man armed with a knife and wearing a balaclava wandering York Street in Sydney's CBD. Officers arrive to find a 41-year-old woman suffering a stab wound at the Hotel CBD on the corner of King and York Streets. A short time later, three members of the public detain the 20-year-old attacker, before he's arrested by police. 3.15pm The body of a 24-year-old woman is found in a Clarence Street unit. * Police investigate whether the body is linked to the earlier stabbing. 5.30pm NSW Police Commissioner Mick Fuller confirms the two crimes are linked and reveals the alleged attacker - 20-year-old Mert Ney - has a history of mental health issues. Police say the Marayong man has no links to terrorist organisations but does have some 'ideologies in relation to terrorism'. Ney was allegedly carrying material 'about other crimes of mass casualties and mass deaths around the world', the commissioner says. Detectives conduct a thorough search of Ney's western Sydney home. Advertisement

It is believed the woman who died in the attack was a sex worker and was known to Ney.

Medication was also found close to the alleged attacker, identified as a drug used to combat anti-anxiety called antinex, Channel Seven reported.

A spokesman for the city's St Vincent hospital said the 41-year-old woman injured in Ney's alleged attack was in a stable condition.

Dramatic footage showed a man, wearing a grey hooded jumper and holding a large knife, jumping on top of a Mercedes while screaming 'shoot me in the head'.

Brave witnesses were able to tackle the man and pin his head down with a milk crate until police arrived and arrested him as hundreds of workers gathered.

In other footage, the alleged attacker was seen running down the pavement and at one point kicked a parked bicycle at a member of the public.

Police praised on Tuesday evening the civilians, fire fighters and ambulance staff for preventing 'what could have been a much worse situation'.

NSW Police said the woman's body was found in the unit on Clarence Street at 3.15pm, with a witness saying it was found on the building's fourth floor.

He added authorities had little doubt the death of the woman in the hotel and the stabbing spree on the street were linked.

'All the information we have at hand would link these two crimes,' he said.

Police were called to King and Clarence Streets in the CBD, near Wynyard Station at about 2pm on Tuesday

Officers on Tuesday evening were searching the alleged attacker's home in Blacktown

What they said about the Sydney stabbing Superintendent Gavin Wood: "A number of members of the public physically restrained the offender. They were significantly brave people. To approach a person with a mindset (that) this person did, with clear evidence of a stabbing previously, these people are heroes." Witness Paul O'Shaughnessy: "My brother, he was the hero. He got a grip of him, along with another guy we don't know, and put a crate on his head. He was just mumbling religious things." Prime Minister Scott Morrison: "The violent attack that took place in Sydney this afternoon is 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 able to restrain him." Federal Labor leader Anthony Albanese: "The details aren't fully known yet but we congratulate the NSW Police on the work that they've done and amazingly brave bystanders who took action to apprehend this man." "Very scary visuals, the fact that people were putting their own lives on the line by taking action was an act of incredible bravery and I certainly pay tribute to them." NSW Police Commissioner Mick Fuller: "All the evidence we have at hand would link these two crimes (the killing and stabbing)." "There was certainly information found on him about other crimes of mass casualties and mass deaths around the world." NSW Police minister David Elliott: "If you want to behave in this sort of manner ... be aware, it's not just the police that'll respond, it's the citizens, it's the firies, it's the ambos, it's anybody else who thinks their city is going to be given that sort of disrespect." Advertisement

Officers on Tuesday evening were searching the alleged attacker's home in Blacktown.

Premier Gladys Berejiklian, who is currently in London, said her thoughts were with the deceased.

'I want to acknowledge the very brave passersby who obviously tried to intervene and our thoughts are with the victims and everyone who witnessed this horrific incident,' she said.

'Do you know how many people you just stabbed, you dog? You just stabbed a chick, mate, in broad daylight,' one of the men was heard screaming during the arrest.

NSW Police Commissioner Mick Fuller have said they found information on the man in the form of a USB stick 'suggesting he had some ideologies related to terrorism'

The alleged attacker was pinned to the ground by heroic bystanders. They held him down with milk crates until police arrived

A woman, second left, is led out of a building on Clarence Street by police after a man allegedly stabbed a woman inside

Moments before the attacker was arrested, another woman was found inside the Hotel CBD with a stab wound and taken to hospital in a stable condition.

A painter working on a mural near where the man was arrested witnessed him charging down the street with a 'big kitchen knife' with five or six people in close pursuit.

The heroic bystanders included two British brothers - one of whom played professional soccer for English club Bury.

Luke O'Shaughnessy watched as the incident unfolded before then subduing the crazed attacker by putting a milk crate over his head.

'It was terrifying mate, it was really bad,' his brother Paul told Daily Mail Australia.

Witness Jess Warren, 28, said she was was having lunch at the Regiment CBD cafe when the knife man was finally arrested.

Police said residents of the Hotel CBD unit block will not be able to return to their homes for several hours while forensic police work at the scene.

One tenant in the building said no-one was being allowed into the building and had been told to wait a 'couple of hours' before being let back in.

'I just walked here from my office, and they're not letting anyone in,' she said.

'Maybe I will just head back there. I'll have to call my [real estate] agent in case they tell him something.'

One person was injured and taken to hospital in a stable condition following the incident on Tuesday. Emergency crews rushed to help the victims

She told Daily Mail Australia fire and rescue workers wielding an axe and a crowbar, and a few civilians, two brandishing chairs, had given chase before finally restraining him.

'One of the guys who was chasing pushed him in the back, then as he was falling the firies got him in the legs, and then they pinned him down with the chairs,' she said.

'Then they just sat on him until the cops came.'

'People couldn't believe it, then everyone started standing on their chairs to see over the crowd.'

Another witness Megan Hales said there was a group of people running away from the knife man but it wasn't clear if he was chasing after them, or running away from the group that was trying to stop him.

One witness who lived at the apartment block next door told The Sydney Morning Herald he heard a woman screaming inside Clarence House apartments and officers then struggled to enter the building.

'The officer and the young man tried to gain the attention of those inside by pressing on multiple apartment buzzers.

Soon after a young woman came to the door, a mobile phone in one hand. Visibly distressed, the woman appealed to the officer: 'you've got to help me.'

A man wearing a grey hoodie covered in blood wielding a large knife could be seen yelling in the street as hundreds of people fled for their lives

Footage shows the attacker being pinned to the ground by hero bystanders carrying milk crates

'I was just acting on instinct': Hero bystander recounts the moment he pinned crazed knifeman to the ground using a MILK CRATE after stabbing a woman and attacking others in Sydney's CBD A heroic bystander has managed to stop a blood-soaked man who allegedly went on a stabbing rampage at Sydney's Wynyard train station on Tuesday just after 2pm. A man wearing a grey hoodie covered in blood and wielding a large knife could be seen yelling in the street as hundreds of people fled for their lives. Luke O'Shaughnessy who watched as the incident unfolded, managed to subdue the crazed attacker by putting a milk crate over his head. 'It was terrifying mate, it was really bad,' his brother Paul told Daily Mail Australia. A heroic bystander has managed to stop a blood-soaked man who allegedly went on a stabbing rampage at Sydney's Wynyard train station on Tuesday just after 2pm 'I was just acting on instinct really. We all just kind of followed suit and just did what we could'. 'Obviously there's something clearly wrong with him, he didn't look normal or anything like that'. 'It was an intense moment. I've got a lot of emotion running high as well. It was pretty scary stuff'. Paul O'Shaughnessy, who owns a recruitment company on nearby King Street, said they heard 'a big kerfuffle and shouting'. 'Luke, my brother, popped his head out and said 'what's going on? There's a guy holding a knife',' he said. Luke O'Shaughnessy chased the attacker and managed to pin him to the ground Advertisement

'At that point there were people chasing him down the street trying to stop him,' Ms Hales, who was at work on Wynyard Street, said.

Ms Hales described the man as being in his late 20s or early 30s, Caucasian and with dark curly hair.

'He wasn't looking in great shape - it was fast.

'A whole lot of guys just came down on top of him and laid him down'.

A barista named Marco, who was working at Batch Café, on York Street, watched in horror as the chaos unfolded.

The Transport Management Centre urged motorists to avoid King Street - south of the city's Wynyard Station - following the alleged attack on Tuesday afternoon

A woman on a stretcher is being taken away in an ambulance from the scene of a stabbing in Sydney

A person can be seen being hauled into an ambulance after the chaos in Sydney on Tuesday

Travel chaos as buses are cancelled, roads are closed and trains are delayed following stabbing frenzy in Sydney's CBD Police were called to King and Clarence Streets in the CBD, near Wynyard Station at about 2pm on Tuesday after a man (pictured) allegedly stabbed a woman with a knife Commuters were left stranded on Tuesday afternoon after a crazed knifeman in the Sydney CBD allegedly sparked a massive police operation. Major roads were blocked off, and the main entrance to Wynyard Station was closed as police investigate the stabbing of one woman, and death of a second. The alleged knifeman was seen on the corner of King and Clarence Street on Tuesday afternoon, wielding a large knife and calling on someone to shoot him. Police blocked off King, Wynyard and Carrington streets just after 2pm. King Street remains closed between Clarence and York, and Clarence Street is closed northbound between Market Street and King Street. Advertisement

'He was trying to smash a driver-side window of a random car with the knife. He was unsuccessful.

'People were chasing him by that stage. There was fireys chasing him with axes and he went around the corner.'

Adrian Papaianni was walking along Clarence Street when when he suddenly heard terrified screams.

'There were a stack of people running down Barrack Place saying that there was a guy with a knife,' he told news.com.au.

Bystanders were told to after a man appeared in the street with a knife

'I ran into the Woolworths and people inside got them to shut the glass doors. I was feeling OK until I saw a mother crying with her baby in her hands, trying to get into the Woolies.

'Police started arriving about a minute later and started to chase him.'

An Uber driver said the knifeman jumped on the bonnet of his car with a knife in his hand and blood on his shirt.

The area has been blocked off by police while investigations continue on Tuesday afternoon

He told 2GB: 'I was next to a fire truck in York Street and he jumped on the bonnet of my car. He crashed across the bonnet and had a knife in his hand.

'There was blood on his shirt. People had their phones out and there was a police'.

A woman at the scene told Daily Mail Australia: 'A crazy man is running around Wynyard with a knife stabbing people.

'My work colleague's boyfriend was standing right next to the guy who was stabbed. Has the world gone mad?'

Officers were seen walking into the Hotel CBD on King Street and speaking with patrons, while others stood guard

Prime Minister Scott Morrison has described the incident as 'deeply disturbing' while commending the bravery over the bystanders who stepped in to help.

'The violent attack that took place in Sydney this afternoon is 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 able to restrain him,' he shared on Twitter.

'The motivation for this attack has not yet been determined as Police are continuing with their enquiries. Any further offical information will be provided by the New South Wales Police, who are keeping us appraised through our agencies, including details of casualties.'

Dramatic picture taken by a tourist in the back seat of a cab shows the crazed knifeman carrying a 30cm blade as a middle aged businessman attempts to bring him to the ground with a chair By Hannah Moore For Daily Mail Australia A gripping photograph shows the moment a brave onlooker holding a wicker chair prepared himself to restrain a crazed knifeman in the Sydney CBD. The man can be seen outside the Hotel CBD on King Street, as the knifeman, believed to be about 25, clutches his knife tightly. Pictured: The moment a brave onlooker prepares to restrain a crazed knifeman on a city road The picture was taken by tech worker Ayusha, who was on holiday in Sydney. 'We just came across the guy with a knife on the street,' she captioned the image. 'Apparently he had some blood on his shirt. We are all safe in the car.' The knifeman was seen jumping on top of a black Mercedes shouting 'Allahu Akhbar' and brandishing his weapon moments before the businessman ran towards him with a chair. 'Oi,' the businessman yelled, ready with his chair. 'Shoot me, shoot me in the f***ing head,' the knifeman yelled as he stormed through the intersection. Advertisement

Onlookers filmed a man being dragged away by police about half an hour after the incident began to unfold.

A number of crime scenes were established and a number of road closures are in place, which is believed to have significant impact on traffic and public transport this afternoon, police said in a statement.

The Transport Management Centre urged motorists to avoid King Street.

A woman was found with a stab wound near The Hotel CBD on Tuesday afternoon

Prime Minister Scott Morrison has described the incident as 'deeply disturbing' while commending the bravery over the bystanders who stepped in to help

'All lanes of King Street are closed from Clarence Street to York Street. Traffic in the area is heavy, and motorists are advised to use an alternative route,' they said.

'Buses are also diverting away from King Street and are using Clarence Street, Market Street, Kent Street and Erskine Street then returning to Clarence Street.

'Emergency services are on site, and traffic crews are responding.'