WARNING: DISTRESSING CONTENT 

The mechanics of a partial hanging - the defence Dr Philip Polkinghorne contends his wife used to kill herself - would have been relatively easy for her to achieve, an overseas expert has told jurors in the eye surgeon’s trial for murder.

But much of the evidence so far from retired pathologist Stephen Cordner cannot be reported - by court order - to anyone outside the High Court at Auckland courtroom, where the sixth week of the high-profile trial continues.

“Some of what I’m going to be talking about is pretty grim stuff, so I apologise for that,” he warned jurors as he began his evidence, which took all morning and is expected to continue well into the afternoon.

Polkinghorne, now 71, is accused of having strangled his wife of 24 years inside their Remuera home before staging the scene on April 5, 2021, to look like a suicide by hanging. Two pathologists called by the Crown earlier in the trial have said both strangulation and hanging were possible reasons for her death due to neck compression.

STORY CONTINUES AFTER THE LIVE BLOG 

STORY CONTINUES 

Given the unclear pathology findings, the Crown has relied instead on circumstantial evidence - particularly regarding Polkinghorne’s allegedly significant methamphetamine habit and an alleged strangling threat in the past. Prosecutors have also focused on the defendant having spent hundreds of thousands of dollars on sex workers and intimate messages with Sydney escort Madison Ashton in which the two appeared to be forming a serious relationship.

But the defence, now in its fourth day, has described all that as a salacious distraction. The real issue, lawyer Ron Mansfield KC has said, is that Hanna had been struggling with depression and alcohol abuse for years. And she had been under immense work pressure as she helped manage the rollout of the Covid-19 vaccination, defence witnesses have said.

Today’s witness, the third pathologist to enter the witness box, is expected to give a more unambiguous opinion of how Hanna died.

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Cordner - a professor emeritus from the Department of Forensic Medicine at Monash University in Melbourne, Member of the Order of Australia and the retired director of the Victorian Institute of Forensic Medicine, which is tasked with conducting the region’s autopsies - said his central task was to determine if Hanna’s death was a homicide or suicide.

But much of his evidence so far has not been specifically about Hanna’s death - rather, a general overview of how suicides and strangling deaths occur and how they are detected. Justice Graham Lang suppressed much of the suicide background, explaining to jurors there was a danger in giving commonly unknown information about the process to people who may be vulnerable.

“We’ve seen a lot of quite distressing things in this case,” he said.

Justice Graham Lang is overseeing the murder trial of eye surgeon Philip Polkinghorne in the High Court at Auckland. Photo / Michael Craig

The Herald has, for similar reasons, voluntarily refrained from publishing non-essential details regarding the possible mode of death during previous witnesses’ evidence.

“The cause of death in many cases is an opinion,” Cordner said as he began the lecture, noting pathologists with the same set of facts can reach different conclusions.

Looking for patterns of injuries is important, but also looking for absence of injuries, he said.

There are a lot of common misconceptions about hangings, he said, explaining that the “judicial hangings” - executions in which a person’s neck is broken - are not what pathologists see. The signs of a “domestic hanging” are more subtle, he said.

“We have to get that [executions] out of our minds as we think about this death,” he said.

For about 70% of homicide cases involving strangulation, there were clear injuries showing a sign of struggle, he said. For the other 30%, there are often specific reasons for which the victim was easy to overpower.

“That, for me, has been a general concern in this case,” he said.

Jurors have learned from the previous pathologists there were no injuries, such as scratch marks on Hanna’s neck, that might indicate a struggle to remove hands or a ligature. There were also no internal injuries detected that were considered to be more common in strangulation than hanging.

Cordner cited an Australian study that found only about a third of people who commit suicide leave a note and about a third have attempted to kill themselves in the past. Police did not find a note in the Polkinghorne home.

One witness, Hanna’s sister, has given evidence that she revealed a self-harm attempt in the 1990s, sometime after the death of their father. That evidence was challenged by prosecutors, who noted no other witnesses - including close friends and family - had heard of such an attempt.

The pathologist is expected to continue his evidence this afternoon.

Craig Kapitan is an Auckland-based journalist covering courts and justice. He joined the Herald in 2021 and has reported on courts since 2002 in three newsrooms in the US and New Zealand. 

The Herald will be covering the case in a daily podcast, Accused: The Polkinghorne Trial. You can follow the podcast at iHeartRadio, Apple Podcasts, Spotify, through The Front Page feed, or wherever you get your podcasts.