Matthew De Gruchy murdered his mum and siblings so violently they resembled crash victims, wiping out most of his family without any explanation.
Now more than 20 years later, one of Australia's most violent teen killers is being released from jail.
The 41-year-old has been deemed fit for release by the NSW Parole Authority, in a move cops involved in the case earlier this year told news.com.au should never be allowed.
He was just 18 when he bludgeoned to death his mother, sister and brother in their Illawarra home in March 1996. He was arrested three months later for the crimes.
He has always denied the killings, insisting he was at the home of his girlfriend and found the bodies when he returned home.
In April, the Parole Authority "formed an intention to grant parole".
But the suburban massacre was so brutal it changed the lives of police who saw the murder scene. One of them, Belinda Neil, told news.com.au De Gruchy should never be released.
Ms Neil detailed the horrific crime in her 2014 book Under Siege.
"He is a sociopath," she told news.com.au.
"I saw the damage to those bodies and their faces.
"He wrote notes, disposed of evidence and never ever admitted or showed any remorse.
"It's really worrisome. I don't think he should be let out at all. I think he's a very dangerous person."
A panel handed down its decision at Parramatta Court this morning as De Gruchy watched via video link from Long Bay Jail, reports the Illawarra Mercury.
He will be released between August 9 and 16.
The newspaper reported De Gruchy sat emotionless for the proceeding.
He will be forbidden entering the Illawarra or Shoalhaven local government areas and will not be allowed to contact any of the family members of his victims.
De Gruchy will only be allowed to contact his father who has indicated he will help him on release.
De Gruchy was sentenced to 28 years in jail and has served 23 years behind bars.
The killings sent shockwaves through the Illawarra community and still haunt the area.
A murder weapon was never found but was thought to be a car jack, wheel brace or similar.
De Gruchy's mother Jennifer's body was found in her bedroom, his 13-year-old sister Sarah's in her bed and his brother Adrian, 15, outside in a shed.
Their injuries were so violent pathologists later said they looked like plane crash victims.
His mum's injuries were so horrific her brain was almost forced from her head.
The coroner needed blood-match samples to identify her.
Adrian had been doused in petrol, while Sarah also had significant head and facial injuries.
De Gruchy's father Wayne, who now lives in Tasmania, was away on family business at the time.
The bodies were "discovered" by a tearful De Gruchy the next morning.
But a sports bag containing items from the house, including a note with De Gruchy's handwriting and pieces of carpet that were cut from the home, were found several weeks later.
The note had a list that included "knife 1", "have shower", "hit arm with pole" and "hit leg with pole".
Small blood stains that matched De Gruchy were also found at the murder scene.
When knocking back a previous appeal, a High Court judgment wrote "the circumstances of these crimes were horrific".
"The mind recoils from the idea that an apparently quiet, gentle young man of good character and with no known reason for an animus against his family should brutally slay his mother and young sister and brother," the judgment continued.