Having fatally gassed her partner and made it look like suicide, Walcha woman Natasha Beth Darcy concocted another cunning plan.
She penned a letter to get a childhood friend to falsely tell police about conversations that the victim had been planning to kill himself.
"(Once I'm acquitted), and I'm pretty much assured if you help me, then I get the inheritance," Darcy wrote.
"I would be willing to give you $20,000."
When writing the letter in January 2020, Darcy was in custody awaiting trial for the 2017 murder of Walcha sheep farmer Matthew Dunbar.
Mr Dunbar, 42, was found dead in his bed on his Northern Tablelands property in August 2017, with Darcy claiming it was suicide.
The friend, who'd visited Darcy a few times in prison, retained the letter and took no further action.
She feigned ignorance when Darcy called a few weeks later, prompting the offender to write a second letter.
"I'm sorry if the amount I offered you offended you. I can give you as much as you need," Darcy said.
After Darcy's NSW Supreme Court trial began, the friend approached authorities to inform them of the letters.
She later gave evidence at Darcy's trial that she'd never spoken to Mr Dunbar. Darcy's lawyer did not cross-examine the friend.
The first letter - which contains a remark that "it's amazing how some people lie" - had explicitly instructed the friend to say she'd offered to talk to Mr Dunbar about his suicide ideation and that, during a 40-minute phone call, he'd said he'd looked up different suicidal methods and "he was convinced we would be better off without him".
"If the lawyers ask for your phone records, just say it was over two years ago and you don't keep them."
The offending wasn't overly sophisticated but did involve planning and wasn't a one-off, Dubbo District Court Judge Craig Smith said on Wednesday.
"It was not at all spontaneous," he said.
That the plan failed held little weight, if any, he said, finding no evidence of remorse or good prospects of rehabilitation.
He sentenced Darcy, who pleaded guilty in the local court to doing an act with intent to pervert the course of justice, to a minimum of two years in prison.
The jury in Darcy's 2021 murder trial found the woman had sedated and gassed Mr Dunbar.
Setting a 40-year head sentence, Justice Julia Lonergan described Darcy as "callous, relentless and heartless" and her lies and methods to kill Mr Dunbar "stupid, clumsy and ugly but ... sadly successful".
Wednesday's sentence extended Darcy's 30-year non-parole period by about six months.
She will now be eligible for parole in May 2048, when aged 73.
