The sister of the man accused of the deadly knife rampage in Sydney has spoken outside the family’s home, saying she is sorry a young woman died in Tuesday’s attacks.

“She was younger than me. She could have been going out within a few hours, to do shopping with her mum, eat dinner with her boyfriend, go speak to her girlfriends … and now she can’t do that, can she?” she said.

“All the words that I can say isn’t ever gonna bring her back, is it? I want to say, I’m really, really sorry. No one should have … she was defenceless.”

#BREAKING: The sister of the #Sydneystabber has spoken for the first time since the attack, outside the families' Maryong home. #9News pic.twitter.com/3a2Cw9vVVg

— 9News Sydney (@9NewsSyd) August 14, 2019

Mert Ney, from Marayong, in Sydney’s west, is expected to be charged with murder and other serious offences when he is released from hospital on Wednesday afternoon.

Michaela Dunn. Photo: Instagram

The body of a woman was found at a Clarence Street apartment on Tuesday afternoon, shortly after Mr Ney was sensationally halted by “heroic’ bystanders on his rampage through Sydney’s CBD.

She has since been identified as Michaela Dunn, 24.

The ABC has been told that Ms Dunn, a sex worker, had been sharing the apartment with another woman, also understood to be a sex worker.

Police sources said the flatmate came back to the apartment yesterday afternoon because she had not heard from Ms Dunn, and found her dead with fatal cuts to her neck.

Joan Westenburg, a friend of Ms Dunn, has paid tribute on Twitter, while lamenting violence against women at the hands of males.

’’I’ve known this girl since she was just a kid in high school at 14. Her sister and I were together for 6 years, and Mikki was like my baby sister. I cannot describe how sad and how broken I am at this moment. I loved this kid. She was incredible,” she tweeted.

Ms Dunn’s flatmate returned to the hotel after not hearing from her for some time. Photo: Instagram

‘‘I am angry that male violence has taken another victim. Selfishly I am so angry that the victim is a young woman I deeply respected and cared about. Mikki was a true delight to know. The violence in this country cannot continue. It cannot.

‘‘I will not stand for her to be attacked as a sex worker. Sex work is work. She was working. She deserved to be safe while she worked. Her job does not make her a lurid story. She was a person and she is now gone. And she is gone because male violence has taken her from us. I have gone so far beyond angry today. I have gone so far beyond sad.

“Australia has a brutal and deadly problem with violence against women. And i miss her.’’

Australian Associated Press understands the stabbing victim is Linda Bo, 41.

Mr Ney will also face other charges – including serious assault – after a stabbing and chase through the CBD.

Police say they have not yet ruled out terrorism as motive for the knife attacks in the city shortly after lunchtime on Tuesday.

On Wednesday morning, investigators trawled through Mr Ney’s electronic devices, social media accounts and the Marayong family home as they tried to determine why the 20-year-old sought to kill and injure innocent people on Tuesday afternoon.

Mr Ney remained under police guard in hospital. He has not yet been interviewed by police about the incident that brought the city’s streets to a standstill.

He was detained by bystanders who gave chase after he was seen wandering the streets and jumping on a car, brandishing a bloodied knife. He was quickly pinned to the ground under a milk crate and a cafe chair until police could arrive.

A dishevelled and bloody Mert Ney after his violent stabbing rampage.

NSW Police Commissioner Mick Fuller said the rampage had not been classed as a terrorist incident and that the “lone actor” had no known links to terrorist organisations.

Mr Ney was, however, carrying a USB stick with information about recent mass casualties in New Zealand and the US.

While he had a history of mental health issues and an “unremarkable” criminal history, his motive remains unclear.

“Having some footage saved on a USB drive is not a leap far enough for me to say that this is a terrorist incident – but obviously it’s extremely concerning and it is the starting point of a long-term investigation,” Mr Fuller said.

“What he has on social media, what we may well find in his bedroom, will hopefully give us, and shine more light on, why this crime happened.”

Mr Ney’s sister said she did not believe he subscribed to extremist ideology.

“All this stuff about extremism, white supremacy, stuff like that, that’s news to me … it was using religion as an excuse,” she said.

On Wednesday, detectives searched Mr Ney’s family home in Marayong and a property in Blacktown, where it was believed he had been staying.

Mr Ney’s family had reported him missing and had concerns for his welfare following a domestic violence incident.

“That is not unusual in terms of what we see day-in-day-out in some houses across NSW [but] that is not a common theme for someone to then take the next step of coming onto the streets of Sydney with a knife and killing people and threatening to kill people,” Mr Fuller said.

Mr Ney has had surgery at Royal Prince Alfred Hospital for a cut to his knee. Police hope he will leave hospital on Wednesday afternoon.

“If we can link him to terrorist activity, then the offences that follow would see him locked behind bars for a very, very long time,” Mr Fuller said.

The commissioner again praised the people who helped restrain the 20-year-old, labelling them “true heroes”.

“They saved lives,” he said.

Commenting on the stabbing victim, who remains in a stable condition in Sydney’s St Vincent’s Hospital, Mr Fuller said it was a “miracle” she was alive.

Police Minister David Elliott said he will ensure police consider any exposure Mr Ney had to government services in recent months as part of their investigation.

“We want to make sure that we learn any lessons that need to be learnt from this particular occasion,” he said.

Police have also appealed for any CCTV, dashcam, and mobile phone vision of Tuesday’s stabbing rampage.

The 41-year-old woman is in a stable condition in hospital.

-with AAP