Terrified screams pierced a leafy suburban neighbourhood as a stabbing attack left a baby girl dead and her mother and grandparents fighting for life.
The residents of affluent Parkinson, in Brisbane's south, were shocked as police van after van tore through windy backstreets in response to an unimaginable domestic tragedy.
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Baby killed in stabbing frenzy
A grandfather is under police guard in hospital after his wife, daughter and granddaughter are allegedly stabbed at Parkinson, in Brisbane's south. Nine News
A neighbour's mobile phone captured what appeared to be the sounds of the two-month-old girl's mother's screams as she fled the house to get help from a neighbour about 2.30pm.
The child's 53-year-old grandfather was seen wandering in the quiet street soaked in blood minutes later before police swarmed and handcuffed him in the driveway.
He remained in police custody in a Brisbane hospital on Thursday morning.
"He was just covered in blood, literally pouring out of him, hey," back neighbour Sun Gill said.
"It was pretty surreal. Very, very surreal, just the blood itself.
"They had the garage door open. You could see all the blood in the garage and then the trail from when they walked to the neighbour's house."
More blood stained the driveway on Watheroo Place between a pair of discarded sandals, as a baby basket rested nearby.
Across the road, officers criss-crossed an otherwise idyllic park with police tape, as residents stopped by to investigate the commotion.
The 28-year-old woman's parents had been visiting from China after the birth of her baby daughter.
The grandfather and his wife, both in their 50s, were in intensive care on Thursday after being operated on in the Princess Alexandra Hospital.
The baby was rushed to the Lady Cilento Children's Hospital with stab wounds but couldn't be saved. Her grandmother was found unconscious inside the house with stab injuries and spent hours in surgery in critical condition on Wednesday night, as did the grandfather.
A police spokeswoman said officers were keeping an open mind about who initiated the attack.
Investigators are yet to formally interview the baby's grandfather, who was visiting from China with her grandmother.
He remained under police guard in hospital on Thursday morning.
The baby's mother had recovered to be in a serious but stable condition by late evening.
The house remained a crime scene on Thursday morning.
General duties police, detectives and forensic officers stayed at the crime scene well into the evening, their vehicles ringing an expansive park.
Regular visitors and even those who lived close by the scene of the attack couldn't hide their shock.
Natasha and Peter Walsh said they often saw the family walking through the neighbourhood but most neighbours in the area didn't really talk to each other.
"It's (usually) very quiet as you can see... Not much happens around here," she said,
"We didn't meet most of our neighbours until today."
- with Kim Stephens and AAP