UPDATE: THE father of a boy brutally stabbed in an alleged domestic violence incident in Sydney this morning has been charged with his murder.
The 36-year-old man was arrested near the family's Carlingford home early this morning and taken to Castle Hill police station where he was charged with domestic violence murder.
He was refused bail and is scheduled to appear at Parramatta Court tomorrow.
Neighbours described the close relationship between the father and son, hours after the five-year-old was stabbed in his northwestern Sydney home.
Natalie and Hank Lewin, next-door-neighbours of the boy and his dad, said they were still in shock over the incident.
"I'm still shaking because we're going to get our kids and I don't even know how to tell my kids; how to tell my kids he's been killed. I don't know," Natalie said.
"He cared for that boy, he was very patient with that boy and he held him and nursed him like he would his son. I can't imagine," Hank said.
"The relationship between the father and the son next door was a doting relationship. He cared for that boy, you could see the boy run to the dad when he needed help."
The Lewins said the family were very friendly neighbours - especially the five-year-old boy.
"He was a really strong little boy. Bold and brave, an outgoing boy," Hank said.
"It's shocking that it's so close to home."
NAN'S FRANTIC DRIVE TO TRY AND SAVE GRANDSON'S LIFE
Trying to flee her grandson's alleged stabber, a distressed grandmother drove the critically injured boy for help.
The woman, 60, turned left out of the small culdesac on another quiet morning in the northwest Sydney suburb, and raced up Pennant Hills Rd heading for a nearby hospital.
Minutes before, her five-year-old grandson had been brutally stabbed by a man known to him in what police allege was a domestic violence incident.
But just a few hundred metres along that road the grandma - who is being treated for shock - had to make a desperate left turn into the first street she came across.
Realising she wouldn't reach a hospital in time, she stumbled upon a childcare centre where paramedics soon arrived to help.
Across the road, members of The Church of Jesus Christ of Latter-Day Saints heard sirens shortly after 7am but were unaware of what had happened until a female visitor arrived at the church at 8.30am.
Members of the church said when the woman stepped off the bus, a policeman approached her and told her a child had been stabbed.
Later, police took the woman from the scene covered in a blanket - believed to be grandmother - into the church to use the bathroom before she left in an ambulance.
The crime scene where the grandma helplessly watched paramedics attempt to save her five-year-old has since been reopened with parents able to pick their children up from daycare.
One father said he had been worried when he heard the incident was connected to the childcare centre but was relieved to find out it wasn't.
"It still doesn't make much sense why they ended up here though," he said.
The grandma's desperate drive, which took her onto Pennant Hills Rd, meant she would not have been unable to turn off again for sometime.
In a Facebook post from last February, the grandmother said the boy "just loves to pretend he is driving AMG."
"He says he wants one when he is bigger," she wrote. "Very impressed with red lights on the inside of the doors."
EARLIER: A FIVE-YEAR-OLD boy has died after being stabbed in what police allege was a domestic incident in Sydney early this morning.
The boy died shortly after arriving at the Children's Hospital in Westmead with stab wounds.
Superintendent Robert Critchlow told reporters the "horrible and brutal" incident was as "bad as it gets".
"At this stage we believe that charges may follow," he told reporters in a press conference this morning. "What's very, very clear is that it's been a horrible and brutal crime against a very young, defenceless boy, which requires a complete investigation, and the matter will go before the courts in due course.
"The level of violence is horrendous. It goes without saying that the fact that a young boy has died from being injured in his home, it's probably about as bad as it gets, really."
Police were called to a home in Carlingford, in Sydney's north west, at about 7am after reports of the alleged dispute.
The child's mother, who was not at the home when the attack happened, is being supported by medical professionals at the hospital where her son died.
The boy and his grandmother had fled the scene and gone to nearby Moseley Street to get help and raise the alarm.
Supt Critchlow said the grandmother's actions were "heroic".
"She's behaved in a heroic and caring manner, as you would imagine a grandmother would," Supt Critchlow said. "She's been presented with something terrible, and done her best to get the young boy to safety and to get him treatment.
"Sadly, despite her best efforts, there was nothing more she could have done. We're grateful to her for what she did do at the scene. She's physically uninjured at this point which we're pleased about. She's also assisting our investigation."
NEIGHBOURS SHOCKED BY THE INCIDENT
Neighbour Mack Lin told news.com.au he was asleep at the time but was shocked when he found out what happened.
He said his niece stays with him weekly and there were plenty of kids in the neighbourhood.
"It's so crazy," he said. "On the weekend there's kids playing, you've got people walking their dogs, walking prams, it's a safe area as far as I'm aware.
"We've never had any issues, any problems, anything along these lines.
"I'm just shocked. I've lived here for 15 years and it's always been a friendly neighbourhood. There's been no stabbings or any violence of that kind."
Mr Lin said he did not know the residents but had waved in the past.
"We see them around, we wave. There's a few kids in this area and we wave to them as you do as neighbours.
"It's really shocking, especially that young. Anybody who would do that to a little child, it's just unbelievable."
A neighbour with a young baby who lives in the cul-de-sac told news.com.au she did not even know a child lived at the property.
Nearby residents added that tenants have come and gone from the property frequently.
Another woman who lives in the street behind said she was in her backyard doing tai chi early this morning and did not hear any commotion.
An elderly couple said they were having breakfast when they heard helicopters flying nearby.
A man and a woman - who are believed to have known the people who live at home - arrived at the scene and spoke to police.
Looking visibly distressed and shaken they spoke to a detective at the police tape and left the scene in a car.
Carlingford: A 5-year-old boy has died from stab wounds following a domestic dispute on Moseley Street. A 36-yr-old man was arrested by police. "This man lives in Carlingford...charges will follow" - Police. #7News https://t.co/kCAHo2CtDz— 7 News Sydney (@7NewsSydney) June 8, 2018
The man told media he would be the spokesman on what happened and would return later to speak to media.
"I'll be making a f***ing statement, you better believe it," he said before getting in the car.
The boy was taken to the Children's Hospital by ambulance and a police escort.
A staff member at the hospital told news.com.au that the boy died just 20 minutes after he arrived a critical condition.
A 36-year-old man was arrested by police and is in custody. He is understood to be known to the boy.
The boy's grandmother, 60, was treated for shock at the scene, while the boy's mother is still recovering at Westmead Hospital.
Inquiries are continuing while the man is in custody at Castle Hill. A second crime scene has been established at a home.
"It's a very difficult situation," Supt Critchlow said. "We put a lot of time and effort in the police in the community to look after our young people.
"As a police officer, I ensure our streets and communities are as safe as possible, and to have a child in his home in my community that I look after pass away through third parties is just heartbreaking, and I think you're going to find it's going to affect the community here."
He added that Carlingford is a "very strong, unified community".
"They're going to suffer very badly from this," he said. "Of course, it has a serious impact on all services involved - the ambulance service and police will obviously be affected by this. "As a community, we're poorer because we've lost a young man today."
Police are urging anyone with information in relation to this incident to contact Crime Stoppers.