A man's involvement with organised crime might have led to his innocent partner's kidnapping and murder and a savage assault on his eight-year-old child.
A group of up to five men broke into a 45-year-old woman's Sydney home and assaulted her and her youngest son before dragging her into an SUV.
The car was found later on Thursday burnt out at Beverly Hills, about 6km away, with a body thought to be the woman's discovered inside after the blaze was extinguished.
The eight-year-old, who was hit in the head with a baseball bat, remained in an induced coma on Tuesday under police guard.
Initially puzzled by the horrific attack, police on Tuesday said the likely motivation was the fact the woman's de facto husband and father to their children was involved in organised crime.
"It appears the male was in some form of conflict with members of that particular organised crime group," Detective Superintendent Joe Doueihi said.
"We believe this organised crime group is based in Victoria, and is responsible for large-scale drug manufacture."
Victorian police raided a property in Springdallah, south of Ballarat, on Saturday in connection with their probe and found evidence of a drug lab.
No charges have been laid as a result of the raid.
The organised crime group consists mainly of Vietnamese men, although police cannot yet draw the direct link between the gang and the men who kidnapped the woman from her Bankstown home.
Det Supt Doueihi called the offences "callous, brutal and against innocent people".
"This woman and her children were in no means involved or had knowledge of what their partner or father was up to, yet they were targeted by this organised crime group," he said.
"These organised crime groups are breaking their own code of conduct by targeting innocent women and children."
The woman had no criminal record, while her male partner was known to police for minor drug offences.
Police said he was interstate on business at the time of the attack and was co-operating with the investigation. He has not been charged with any offence.
His son is expected to suffer lifelong complications from the attack.
The boy had emergency surgery for serious head injuries on Friday and medical staff hope to bring him out of the induced coma on Tuesday.
His 15-year-old brother was not physically assaulted, but suffered psychological injuries from what he witnessed, police said.
He also remains in hospital under police guard.
A post-mortem scheduled for Wednesday is expected to confirm detectives' strong belief the body found in the car is the 45-year-old woman.
The body was so badly burnt police have not been able to formally identify it.
NSW Police have not been able to contact relatives in Vietnam of the dead woman, with no other relatives known in Australia.
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