A NSW woman who was the sole beneficiary of her grazier partner's estate has gone on trial for murder accused of sedating and gassing him.
Natasha Beth Darcy pleaded guilty to aiding and abetting suicide, but prosecutor Brett Hatfield told the jury the Crown rejected the plea and contended she killed Mathew Dunbar.
The 46-year-old has pleaded not guilty in the NSW Supreme Court in Sydney to murdering the 42-year-old sheep farmer on his property Pandora in the country town of Walcha on August 2, 2017.
In the crown opening address on Wednesday, Mr Hatfield said the property was valued at $3.5 million and in 2015 Mr Dunbar made a new will leaving all of his estate to Darcy.
He alleged this was Darcy's primary motive to murder her partner by faking his suicide as she stood to inherit all the property.
Much of the crown case centred of many internet searches made over a period of months on various phones and a computer, searches which Mr Hatfield alleged were made by Darcy.
"The accused acknowledges she made some but not all the searches," he said.
"She has suggested the deceased made a number of them."
Search topics included poisonous spiders and mushrooms, toxic plants, suicide methods, how to commit murder and "can police see websites you visit on your mobile".
After the couple had dinner and shared some red wine, Darcy allegedly mixed a number of sedatives in a blender, which she gave to Mr Dunbar in a drink in a glass tumbler.
At 1.14 am on August 2, Darcy's husband - a paramedic from whom she had been separated for some time - received a text saying: "tell police to come to house, I don't want Tash or kids to find me".
Darcy rang triple-zero at 2am saying she had discovered her partner in his bed with a plastic bag and a gas cylinder.
Mr Hatfield is continuing his address.
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