Knife used to kill Maureen Boyce was reinserted several times, a forensic pathologist tells court.

A forensic pathologist has given gruesome details to the Supreme Court about the way in which former model Maureen Boyce died in her Kangaroo Point penthouse 2015.

Former model Maureen Boyce was found with five separate knife “tracks wounds” in her body, indicating the blade was likely withdrawn and reinserted several times, a forensic pathologist has told a court.

The evidence was given on the fourth day of the Supreme Court trial of Thomas Chris Lang, a retired American doctor who has pleaded not guilty to murdering his lover, 68-year-old Ms Boyce in 2015.

Model Maureen Boyce during her modelling days in early 70's.

Forensic pathologist Beng Beng Ong examined Ms Boyce’s body after she was found dead in her bed with a kitchen knife with a 19cm blade buried to the hilt in her abdomen.

Mr Ong has today given evidence he located five separate “tracks” the blade had travelled along and three separate exit wounds from her back.

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The knife penetrated the woman’s liver, cut her bile duct, fractured a rib and caused a “catastrophic” haemorrhage by penetrating a major vessel that all lower body is pumped through to return to the heart.

Mr Ong said two of the track marks were made with the blade at one angle while three further track marks were made at an entirely separate angle, meaning the blade was likely pulled almost all the way out and reinserted.

Model Maureen Boyce during her modelling days in early 70's.

He said for the sets of two and three track marks made in the same direction, the blade could have withdrawn as little as one centimetre before being thrust inward again.

“So between the two tracks in A and the three tracks in injury B, there’s been a short withdrawal of the knife in between each of themselves but between the causing of A and B there has to be a significant pulling back of the knife and a changing of the direction of the knife before those three tracks have been (made),” Crown Prosecutor Todd Fuller asked to clarify the evidence.

“Yes,” Mr Ong replied.

Maureen Boyce during her modelling days.

The crown alleges Lang murdered Ms Boyce but defence barrister Ruth O’Gorman told the jury at the start of the trial on Monday that DNA belonging only to Mrs Boyce was found on the blade and there was no medical evidence she had struggled.

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“The issue in this trial is whether Ms Boyce was killed by Mr Lang or whether she committed suicide,” Ms O’Gorman said.

“We will submit that the evidence establishes that Ms Boyce killed herself.”

The trial continues.