A young Queensland woman, with an "unnatural interest" in seeing people die, has been jailed for at least 21 years for the stabbing murder of her grandfather amid a plot to steal his life savings.
Brittney Jade Dwyer stabbed 81-year-old Robert Whitwell four times, then paused to do the dishes, as she waited for him to die at his Adelaide home.
Just 19 at the time, she had driven to Adelaide from Brisbane with her 21-year-old friend Bernadette Burns in August last year with the intention of robbing her grandfather of more than $100,000 he kept stashed in his backyard shed.
The pair pleaded guilty to murder, with Burns jailed for at least 13 years and six months for her part in the killing.
Sentencing the women in the Supreme Court on Tuesday, Justice Kevin Nicholson described Dwyer's offending as evil and abhorrent and she remained a danger to the community.
The judge said she was motivated by greed and an "unnatural interest with violence and with seeing people die".
"This murder was brutal, callous, cold-blooded and dispassionately planned," he said.
When they arrived in Adelaide in February, the killers went to Mr Whitwell's northern suburbs home.
Dwyer, who had packed a bag with bolt cutters, tin snips, a hammer, gloves, cable ties and a knife, spent some time talking with him before pulling out the knife and stabbing him in the neck and chest.
"Strangely you assisted Mr Whitwell to apply a band-aid to one of the cuts and used a cloth to help clean off some of the blood," Justice Nicholson said.
"While you were waiting for him to die, you busied yourself washing the dishes."
Mr Whitwell's body was found slumped in a chair three days later.
Justice Nicholson detailed Dwyer's problems with drug and alcohol abuse and said she had been diagnosed with a borderline personality disorder along with anti-social traits and problems with rage.
He questioned if she had the ability to be contrite said the killing was a tragedy on two fronts.
"The very same people who have been badly damaged by the sudden and violent end to the life of Mr Whitwell are simply shattered by the fact that it was such a close member of the family, you Miss Dwyer, who so callously and brutally murdered him," he said.
"One can hardly imagine the pain and distress your mother must be feeling having seen her father killed in this way by her own daughter."
Outside court, Mr Whitwell's brother Geoffrey said the family felt the sentences were adequate and ended a difficult time.
"We just have to know and be glad that it's all over and we can get closure," he said.
"Let the healing begin."
Mr Whitwell said his brother was a gentleman who always tried to do the right thing.
"You couldn't get a better brother," he said.
