A Launceston couple used their murder victim's phone and Facebook account to send messages to the deceased's family for seven months as part of a "cunning" and "sophisticated" plan to cover up the killing, a court has heard.
Ian Rosewall, 47, pleaded guilty to murdering 24-year-old Tyson Timothy Clark-Robertson, while his partner Renae Lorraine Donald, 21, pleaded guilty to being an accessory after the fact of murder.
They both previously pleaded not guilty, but changed their pleas earlier this year.
Mr Clark-Robertson was last seen alive in July 2016. Nine months later his body was found buried in a shallow grave in the backyard of a Mayfield property.
During sentencing submission, crown prosecutor John Ransom told the Launceston Supreme Court the trio and another man, Robert William Broad, lived together at the Mitchell Street property when the murder took place.
Donald had previously been in an 18-month relationship with the victim, but started dating his killer in the weeks before the murder.
Mr Ransom said Rosewall and Mr Clark-Robertson were drinking alcohol and smoking cannabis together while putting up makeshift window curtains on the morning of July 20, 2016.
He said Mr Clark-Robertson told Rosewall to "get me another cone, you paedo dog".
"Mr Rosewall said he lost it, he picked up a hammer and struck Mr Tyson Clark-Robertson," Mr Ransom said.
It's believed Mr Clark-Robertson was struck up to five times in the head.
Killer 'would have given victim CPR if he knew how'
Mr Ransom said the accused admitted his actions to a psychologist in Risdon Prison last year, claiming he "was angry as hell, but didn't think I'd hit him that hard".
"He said he would have given CPR if he knew how to do it," Mr Ransom said.
"He didn't want to report Mr Tyson Clark-Robertson's death because there were warrants out for his arrest."
The court heard the murderer kept his victim in a "silver garden shed" before burying him in their backyard days later.
The couple attempted to cover up the murder by using the deceased's phone and Facebook account to pretend to be him, the crown said.
They also withdrew Mr Clark-Robertson's disability support pension — which was going into Donald's account from when they were dating — and pretended they were catching up with their victim each week to give him the cash for it.
"It's the state's case that Ms Donald and Mr Rosewall embarked on a joint and sophisticated strategy to prevent the murder being discovered by police or Tyson Clark-Robertson's family," Mr Ransom said.
He said while it was not believed that Donald played a role in the murder itself or the burial, she assisted in the cover-up.
"It's the state's case that Ms Donald assisted Ian Rosewall in trying to cover up by firstly lying to police about Tyson Clark-Robertson's whereabouts," Ms Ransom said.
Victim's dad 'traumatised'
The state also alleged Donald sent messages to Mr Clark-Robertson's dad, Tim, from July 2016 through to February 2017 to make it seem like his son was still alive.
Some requested money, while others claimed Donald was pregnant with twins that belonged to the deceased.
The dad became suspicious of who the messages were coming from and contacted police, which is when the murder investigation commenced.
In a victim impact statement read to the court, Mr Clark-Robertson's dad said he had been diagnosed with post-traumatic stress disorder after finding out his son had been murdered.
"I feel like I have been traumatised, manipulated," he said.
"I always wanted him to carry on my family's name, he's my only son, and that's been taken away from me."
Both Ms Donald and Mr Rosewall's defence lawyers are yet to make sentencing submissions.
They requested adjournments to prepare mental health reports on their clients.
