Walcha murder: Natasha Beth Darcy-Crossman allegedly searched internet on 'how to murder', 'poison' Mathew Dunbar, police allege

No bail: Natasha Beth Darcy-Crossman, 42, is charged with murdering Mathew Dunbar on August 2, at Walcha. Photo: Supplied

No bail: Natasha Beth Darcy-Crossman, 42, is charged with murdering Mathew Dunbar on August 2, at Walcha. Photo: Supplied

DETECTIVES will allege a Walcha woman Googled if ‘helium showed up in an autopsy’ less than two hours before she allegedly murdered her de-facto partner at his sheep property.

New details in the case of Natasha Beth Darcy-Crossman, who now goes by the name of Darcy, have emerged after she was again refused bail on Monday, charged with murdering Mathew Dunbar.

Fairfax Media can also reveal that it is the police case that Darcy lied to investigators, used aliases and false names to allegedly source drugs, and researched then deleted web browser searches on how to commit murder.

As part of their case detailed in police facts, police will allege in the nine days prior to Mr Dunbar’s death, Darcy allegedly searched ‘murder by injection, ‘the science of getting away with murder’, ‘99 undetectable poisons’, ‘arsenic’ as well as various methods of suicide.

Police will allege that many of these searches relate to certain methods of causing death that are undetectable or hard to locate during a post-mortem, and were allegedly deleted from her phone, but were recovered by police.

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Strike Force Ballin – the Oxley detectives-led police operation – alleges Darcy made the search on Mr Dunbar’s phone at 12.31am on August 2, just an hour-and-a-half before paramedics and police were called to Pandora, outside of Walcha, to reports of an unresponsive male.

Mr Dunbar died at the scene.

Police allege Darcy placed a quantity of drugs and animal sedatives into his food and drink on August 1, sedating him, before allegedly placing a plastic bag over his head and secured it with elastic before turning the tank of helium on, attached to the bag via a hose.

Mr Dunbar had at least five prescribed drugs in his system, according to toxicology reports, and that Darcy’s DNA, as well as that of Mr Dunbar’s was allegedly found on the bag around his neck.

Detectives allege Darcy-Crossman also used her partner’s phone to text her ex-husband, telling him at 1.13am, “Tell the police. I don’t want Tash and the kids to find me”.

At 2am, Darcy allegedly used the same phone to contact triple zero to report she had found her partner in bed and “that he had gassed himself”, police allege.

Detectives allege while on a visit to Tamworth on August 1, Darcy used her mobile phone to search the internet for items such as ‘euthanasia device’ and ‘suicide/suffocation/helium’, as Mr Dunbar went into a Peel St restaurant to order their lunches.

Police will also allege specialist officers found deleted web browser searches “which related to whether police could ‘track private browsing, do internet providers keep user history and suicide bag’”.

As part of their case, it’s alleged Darcy searched the internet for ‘suicide bag’ and ‘helium filled exit bag’ one day before she allegedly murdered him.

On August 1, Mr Dunbar and Darcy had seen an orthopaedic surgeon at Tamworth hospital as he was treated for an infection in his mouth and leg, who told the 42-year-old alleged victim he was happy with the progress of his leg, police allege.

On the same day, the pair dropped a quad bike off for repair, picked up a bottle of helium in Tamworth and allegedly told staff it was for an event they had coming up, and then went shopping, carrying out a number of odd jobs in town.

Police will allege Darcy told them when they arrived at the property, off Thunderbolts Way in the early hours of August 2, that Mr Dunbar appeared depressed, after he “received bad news about the infection in his leg and that it would never be completely right” and had bought the helium bottle “which he told her was for welding”.

Darcy has not been required to enter a plea to the charge of murder. On Monday, she stayed in the Tamworth Police Station cells and did not appear in court.

“No application for bail on this matter this morning,” Legal Aid solicitor Garry Johnston said, a day after she was refused bail in the same court.

“Ms Darcy does not wish to be before the court.”

Mr Johnston asked for a “medication review” of Darcy-Crossman by Justice Health, while in custody.

Magistrate Roger Prowse formally refused bail and ordered the 42-year-old accused to remain in custody until the case returns to court on January 24.