The sister of cold case murder victim Martin Meffert has told a South Australian court that the crime has changed her "outlook on the world" after it went unsolved for more than a decade.
Mr Meffert, 23, was last seen alive on February 8, 2005, and the Supreme Court was today told he was "likely" murdered the following month.
The court heard that the "partial remains" of Mr Meffert were found in a sports bag inside a plastic tub at the killer's Terowie home, in the state's Mid North, in October 2013.
The 32-year-old killer, who cannot be named because he was 16 at the time, was arrested in 2018 and pleaded guilty to murder the following year.
Justice David Peek ordered him to serve the mandatory sentence of life in prison for murder but is yet to set a non-parole period.
In her victim impact statement, the victim's sister Natasha Meffert today questioned how the defendant could keep the murder secret for so long.
"We always thought Martin would get in contact when he was ready — little did we know that was never going to happen," she said.
"When our mother died, we tried every avenue possible to try and find Martin so he could attend the funeral. This was not possible as he was already deceased.
"It took 15 years for you to plead guilty — how could you have kept this from your family?
"You have affected my outlook on the world. I will never forgive you for what you did to Martin."
Killer stole disability support payments
Prosecutor Kos Lesses told the court the murder was serious given the vulnerability of the victim, financial motivation for the murder, concealment of the crime and the treatment of Mr Meffert's remains.
He said the killer stole $136,000 of disability support payments from the victim's bank account for nine years after the murder.
"He did, quite literally, cash in on his crime for almost a decade," he said.
He said the defendant initially buried his victim in a shallow grave at his parents' property before moving the remains to a different house in a wheelbarrow in broad daylight.
Scott Henchcliffe SC, for the killer, told the court his client was financially motivated to murder his victim.
"It wasn't a spur-of-the-moment thing," he told the court.
He said Mr Meffert gave the then-teenager his bank card and PIN number so he could buy an iced coffee from a local deli, which sparked his intention to kill.
"His actual motivation for doing so was to take Mr Meffert's bank card and he could use that money to fund his drug use," He said.
"He was high on drugs that day — he ruminated about the idea that came to him about murdering Mr Meffert.
"He collected an old shotgun from a nearby abandoned house and shot him in the head deliberately while he slept."
Mr Henchcliffe asked the court to set a non-parole period lower than the mandatory minimum of 20 years because his client confessed to the crime and helped investigators find the rest of the victim's remains in 2018.
But prosecutors submitted that the killer only assisted authorities after his arrest when the evidence was "stacked up against him".
Justice Peek will set a parole period at a later date.
