An Illawarra man convicted of bludgeoning three family members to death in a scene so bloody and horrific it traumatised police investigators has warned his family their life is about to change ahead of his imminent parole hearing.
Matthew De Gruchy was just 18 when he murdered his mother, sister and brother in the family home, their bodies so badly beaten their injuries were described as something similar to plane crash victims.
De Gruchy has always denied the killings carried out in a scene of gore in the family home in Albion Park Rail in March 1996, telling police he was at his girlfriend's house at the time.
He was sentenced to a maximum 28 years jail but will have a private parole hearing on Thursday.
Ahead of his hearing, the 38-year-old sent a letter to family members seemingly out of the blue, News Corp reports.
The letter contained the usual pleasantries, Matthew De Gruchy wishing the family well.
But the letter also reportedly contained some lines suggesting things would change for the family that has shied away from the spotlight since the brutal slayings south of Wollongong.
De Gruchy is said to have admitted in the letter how his upcoming parole hearing was playing on his mind but he was looking forward to it.
One unnamed family member said they could not understand how someone like De Gruchy could be allowed back into society after carrying out such horror, believing killers like him had "lost their soul".
"They can't be rehabilitated, I don't think they can be ever changed after something like murder," the relative said.
"Surely he can't think he will just slip back in like nothing has ever happened?"
During the criminal trial it was argued that De Gruchy murdered his mother Jenny and two young teenage siblings Adrian and Sarah after an argument about borrowing the car.
His father Wayne, who was away on business in Sydney at the time of the killings, stood by his son throughout the trial, disbelieving the teen had carried out the slaughter.
Following his son's conviction, however, it is understood the father made contact with the police investigators so he could examine the evidence gathered in the case.
One piece of evidence used against De Gruchy was a checklist, scribbled on a scrap of paper the Crown argued was evidence of the crime's cover-up.
The note, found in a bag hidden in the bushes near his girlfriend's house, included entries such as "Sarah, Mum, Adrian", a list of items of clothing, "throw bottle down the back", "throw things over wall", "Cut somewhere with knife", "hit arm with pole" and "hit head on bench".
De Gruchy told police he returned home find his mother and siblings slaughtered, screaming out and running next door to a neighbour's shouting "something's happened to mum and Sarah".
He was later taken away from the murder scene in an ambulance.
One police officer who investigated the scene was so traumatised they left force.
Former homicide detective Belinda Neil later described a blood-spattered home in a book, Under Siege.
"Whoever had killed this family had really gone berserk and inflicted incredible injuries. I still couldn't comprehend that a human being could do this to another human being," she wrote.
Mrs De Gruchy's body was found in her bedroom, her head so badly bashed her brain had almost been squeezed from her skull.
Blood found in the 41-year-old's airways indicated she had survived for a short while after she was bludgeoned.
Sarah, 13, was found in her bed, detectives determining De Gruchy surprised the mother and daughter as they slept.
Sarah's arms were covered in bruises, an indication she woke up and tried to defend herself from the assault.
Adrian, 15, was found in the back shed, covered in petrol and 21 separate wounds that left blood spatters on the ceiling.
Police never found the murder weapon but they believed it was a car jack or something similar.
De Gruchy was charged with the triple murder three months later.
He has always denied the killings but it is believed he has already been on day release.