Police initially said Mr Nisbet’s death was suicide, but the detective efforts of Australian-based Lee-Anne Cartier led to the case being reopened.
On Thursday, Helen Milner, 50, was jailed for 17 years for murdering her husband by crushing up an antihistamine drug he was allergic to and putting it in his food. She then tried to make it look like a suicide.
Ms Cartier is taking legal action against police for their bungling.
Sensible Sentencing Trust spokeswoman Ruth Money says the matter is now being dealt with by lawyers and no comment would be made. The trust has been helping Ms Cartier and her family throughout the trial.
However, earlier this year, Ms Cartier told AAP police knew it was a murder.
“They said: ‘we know she did it, we don’t have the level of evidence to convict’,” she said.
“They knew well and truly. They made their statements to the coroner saying they thought it was suicide, but they knew she murdered Phil. They just couldn’t be bothered doing their job.”
Despite being based in Australia, Ms Cartier kept carrying out her own investigation.
She rang people and then would chase up the police, showing them her information.
That included her telling them to speak to a neighbour about the lights being on at 4.20am and to also contact Milner’s boss.
“She’d told me a heap but police never interviewed her.
“It’s a joke. It’s a complete and utter joke. It was like sending kindergarten kids to do a grown man’s job.”
In a statement following Milner’s sentencing, Detective Inspector Tom Fitzgerald said police had discussed with Ms Cartier reimbursement of costs she incurred prior to the coronial inquest.
“Ms Cartier indicated she was not satisfied with this, and intended to pursue wider compensation,” he said.