The information came to light at the Ballarat Magistrates' Court on Wednesday, during day two of a committal hearing for the four people accused of murdering Kobie Parfitt.

During the hearing the prosecution is presenting its case to Magistrate Ron Saines and the defence lawyers for the four accused - Shannon Jeffrey, Jacob Ford, Renee Reynolds and Brendan Prestage - are able to cross examine the witnesses.

Four people gave evidence to the court on Wednesday.

On Wednesday morning forensic toxicologist from the Victorian Institute of Forensic Medicine, Maria Pricone, was the first to give evidence.

The court heard she had analysed blood and other specimens for analysis in the case.

She found various chemicals in the specimens, including acetone and isopropanol, but she told the court she could not determine whether they were the result of Parfitt's metabolic processes while she was still alive or if they formed post-mortem.

During cross-examination she said the levels were not so high as to indicate Parfitt had ingested the chemicals but she could not rule it out.

The court also heard methylamphetamine and amphetamine were found in Parfitt's system.

A second witness, a forensic pathologist who undertook an autopsy on Parfitt's body after she was found in December 2020, also gave evidence.

Yeliena Baber, who has extensive experience giving evidence in court cases, told the court that she could not determine how the 43-year-old had died, despite extensive testing, as her body was in such an advanced state of decomposition by the time she was found.

While the court heard she was "wrapped in various coverings", the decomposition was the result of her body being dumped and left down a mine shaft for an estimated eight months.

She said the decomposition meant that any subtle injuries, such as soft tissue injuries that would not break a bone, might have been erased - describing examples such as bruising, scratches or even deeper skin or soft tissue wounds.

"It is very difficult to ascertain whether something had happened with that degree of decomposition and the breakdown of tissue," she said.

The state of decomposition and the way the autopsy was performed also meant she could not determine if Parfitt had been stabbed or a victim of blunt force trauma but she could not rule out asphyxia or haemorrhaging.

While she said breaks or fractures to the bones would have been evident during the post-mortem, she did not find evidence of these.

One defence lawyer asked if anything in Parfitt's medical history, which included inflammation of the gallbladder and a kidney infection, could have resulted in her being seriously ill.

Ms Baber said serious illness or death was unlikely unless Parfitt failed to receive appropriate medical care.

She also added that consumption of illicit drugs and alcohol would not have exacerbated the two conditions.

An expert in telecommunications for Telstra was also cross-examined by the lawyers. Adam Gelfe told the court that records showed a phone travelled from Mount Clear into Ballarat and was then pinging between three different phone towers - Snake Valley, Linton and Mount Hollowback.

His analysis indicated the phone was "most likely" stationary near Cochrane Drive for about two hours.

Factors which might affect the strength of a signal could be trees, buildings, hills or cars and it meant the tower the phone was connected to was not necessarily the geographically closest because it would buffer between different towers to maintain coverage.

A fourth witness, a police officer from the Missing Person's Squad, also gave evidence to the court.

Detective Leading Senior Constable Kerryn Makin was cross examined by lawyers about a recorded interview she conducted with Ford when Parfitt was still a missing person.

The day's evidence came after four witnesses gave evidence on the first day of the hearing, on Tuesday, about seeing and speaking to Parfitt in the weeks and days before she is believed to have been murdered.

The court heard she had been living in fear and was in the process of moving out from her Hickman Street address because she feared for her wellbeing.

Parfitt was last seen alive at the Ballarat property she was renting on April 28 last year. Her remains were found down a mine shaft in Snake Valley on December 22 following an extensive police search.

The four accused have each been charged with one count of murder but are contesting the charges.

The committal will continue on Thursday. At its conclusion, Magistrate Saines will decide whether there is enough evidence for the case to proceed to trial in the County Court.

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