An Australian woman has been found guilty of murdering her partner by drugging him with a sedative cocktail blended in a Nutribullet and gassing him in his bed in a bid to inherit his A$3.5 million (NZ$3.7m) farm.
In the months before Mathew Dunbar was found dead, dozens of incriminating searches were recorded on Natasha Darcy's iPhone, among them: "How to commit murder."
A jury of 11 declared the 46-year-old mother guilty today after deliberating since last Wednesday.
Dunbar, 42, was a sheep farmer who lived and worked on his property Pandora on the outskirts of Walcha in northern NSW.
Darcy claimed she found her partner of three years in the early hours of August 2, 2017, after he had attempted suicide. She rang emergency services and he was declared dead at the scene.
Mathew Dunbar was murdered in August 2017. Photo / Supplied
The ram sedative acepromazine and medications temazepam, clonidine and seroquel were found in both Dunbar's blood and a dirty blender cup and glass left in the dishwasher.
Darcy pointed to Dunbar's finances, history of depression and suicidal ideation, "unclear sexual orientation" and a severe calf infection he suffered weeks before his death as reasons he might have killed himself.
But her search history told a different story, the jury heard during the 10-week trial in the NSW Supreme Court.
The Crown said Darcy conducted extensive online research and even embarked on two "dry runs" before finally killing Dunbar, staging his death to make it look like a suicide.
Searches about poisonous mushrooms and spiders were first recorded on her phone in February 2017.
In the ensuing months, dozens more searches related to murder, death and suicide were made.
Among them were "lethal dose of oxycodone 200 pound male", "acepromazine murder", "can police see websites you visit on your mobile", and, from the sideline of a rugby game, "how to commit murder".
Natasha Darcy and Mathew Dunbar had been together for three years. Photo / Facebook
At the same time, prosecutor Brett Hatfield said, Darcy was making real-world preparations to kill Dunbar.
She exaggerated Dunbar's depression to other people to "lay a trail" before the staged suicide, and taunted the sheep farmer about the rafters in the shed not being high enough to hang himself, Hatfield said.
She tried at two different veterinary clinics to obtain acepromazine but was rebuffed — the first vet growing so alarmed by the request that she called the police — before eventually obtaining a 100ml bottle from a clinic in Armidale.
Darcy landed on the idea to use gas to kill him as she browsed Google during a trip to Dorrigo, the court heard, and she rang Supagas in Tamworth to order a 3.5 cubic metre bottle of pure helium on July 31, 2017.
Darcy and Dunbar together picked up the bottle on August 1, hours before he died.
At 1.14am on August 2, 2017, a text was sent from Dunbar's phone to Colin Crossman, a local paramedic and Darcy's ex-husband. (The pair remain legally married but separated in 2012.)
It read: "Tell police to come to house, I don't want Tash or kids to find me."
The crown said the message was a fake suicide note composed by Darcy.
Crossman said he did not see the message until after he received the emergency alert at 2.02am.
He and another paramedic were the first to Pandora and declared Dunbar dead at 2.44am.
Eight years earlier, shortly after taking out a A$700,000 life insurance policy, Darcy had launched attacks on Crossman, hitting him on the temple with a hammer while he slept.
Three days later, she set the house alight while he slumbered under the influence of several sedatives he did not knowingly take.
The last thing Crossman recalled before waking up surrounded by flames was watching the cricket and eating tacos prepared by Darcy.
After she was arrested in November 2017, Darcy wrote to a friend while in custody and offered her A$20,000 to lie about Dunbar's depression and suicide attempts.
Prosecutors said Darcy's motive was inheriting Pandora, then valued at A$3.5 million. Photo / News Corp Australia
The friend cut off contact. Darcy wrote to her a second time, apologising if she was offended by the amount offered and said she would give her as much as she needed.
As she pleaded not guilty to murder at the beginning of her trial, Darcy said she had aided and abetted Dunbar's suicide.
But no evidence to support that came to light over the next 10 weeks, and the jury was told to put it out of their minds by Justice Julia Lonergan.
