• Natasha Darcy was charged with murdering sheep farmer Mathew Dunbar
  • She allegedly did so to inherit his $3.5m property
  • Darcy had searched for "can police see websites you visit on your mobile"  ​

A woman in Australia searched "how to commit murder" on the internet five weeks before she allegedly served her husband a sedative-laden smoothie and then gassed him to death with helium.

Natasha Darcy, whose trial began at the Australian Supreme Court on Wednesday, was charged with murdering sheep farmer Mathew Dunbar to inherit his $3.5m property, The Sydney Morning Herald reported.

The court was also told by the prosecution Darcy used a Nutribullet to blend sedatives into Dunbar's drink on the evening of Aug. 1, 2017. The farmer, who drank it, then went to bed, sedated.

Prosecutor Brett Hatfield told the court in the early hours of the next day, Darcy covered Dunbar's head with a plastic bag and fastened it with an elastic band. She then connected a hose from the bag to a helium cylinder and turned it on, The Sydney Morning Herald reported.

Around 2 a.m. (11 a.m. ET on Aug. 1) Darcy informed the emergency services that Dunbar was unresponsive with the bag over his head. Paramedics, who arrived at the scene, failed to revive him.

Hatfield told the court Darcy began searching in February 2017 about "body breakdown spider venom" and “poisonous fungi Australia,” reported.

By March, her searches were about “arteries in the body” and “can police see websites you visit on your mobile.” Darcy also searched “how to commit suicide” and “food processor recipes” in April, the prosecutor said.

It was during one of these searches that Darcy clicked on helium gas. Following this, the couple went to Tamworth on Aug. 1 and picked up a helium cylinder, which Dunbar told the clerk was for him. Further investigation revealed the presence of sedatives in the blender cup and a glass tumbler used to serve Dunbar.

The prosecutor also told the court about previous incidents involving Darcy where she allegedly set her ex-husband's bedroom on fire when he was sleeping. She was also accused of drugging him in tacos, after traces of drugs were found in his body fluids, which her ex-husband said he didn't take knowingly.

Darcy has denied the murder charges and the trial continues. However, she has since admitted to aiding and abetting Dunbar’s suicide.

Representative image AFP / Johannes EISELE