WARNING: DISTRESSING CONTENT
“When I got her down it looked too hideous to me. I undid the granny knot upstairs. It looked awful just hanging there. It was just horrible, the rope.”
That was the explanation eye surgeon Philip Polkinghorne gave to police on April 5, 2021 - just hours after the reported suicide of his wife started to be instead treated as a suspicious death - about why the bright orange rope found dangling near her body was unexpectedly loose when investigators arrived.
The statement, from a yet unplayed three-hour police interview, was read aloud by Polkinghorne’s lawyer today as the Crown continued to call evidence on the fourth day of Polkinghorne’s six-week murder trial. It was intended to rebut the findings of a Canadian knot expert who spent the entire first half of the day testifying via audio-video feed from overseas.
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Robert Chisnall, who has published papers and authorised a manual on knot tying for forensic investigators, came up with a simple conclusion: the rope, as it was found tied by police, could not have been used in a suicide by hanging.
“It was an insecure grouping of tangles with additional slack on the floor,” he said. “It was too long and too insecure to suspend any weight.”
Polkinghorne, 71, is accused by prosecutors of having strangled wife Pauline Hanna, 63, inside their Remuera home - possibly while high on methamphetamine and during a heated confrontation over finances or his expensive extra-marital affairs with prostitutes - before staging the scene to look like a suicide.
The rope has become one of the central focuses over the past two days, although not the only evidence prosecutors are relying on. The Crown has acknowledged the case against Polkinghorne is circumstantial, meaning there are numerous small pieces of evidence that they have predicted will fit together like a jigsaw puzzle to form a complete picture of what occurred.
The defence, meanwhile, has said police had a fundamental misconception about what had occurred from the get-go, leading to a biased investigation that resulted in a murder charge 18 months later despite no solid evidence to support it.
Today’s expert testimony came after two detectives testified yesterday that their suspicions were first triggered after viewing the rope that was reported to have been used in Hanna’s suicide. A series of “granny knots” were tied across three bannisters at the top of the stairs. The knot had not slid down to the base of the railing and could easily be moved up and down when given a slight push, the investigators testified.
Chisnall, the knot expert, drew detailed sketches of the knot and recreated it at his home in Canada using multiple varieties of rope he had in storage. He used two different balustrades - one on his back deck - then conducted over 20 tests to see how the rope and the knot reacted.
“Very little force was required to cause it to collapse,” he testified, explaining that he yanked on the ropes while using a luggage-weighing device to calculate the amount of force needed to make the knot slide down the bannister. “The force didn’t even register on the gauge. It was under 1 kilogram.”
The witness denied, under cross-examination from defence lawyer Ron Mansfield KC, that having the actual balustrade and rope for his experiment would have changed the outcomes. He could have tied any rope to any balustrade and, given the way the knot was tied, it would have reacted the same way, he insisted.
But Mansfield also suggested during cross-examination that the expert didn’t have all the evidence necessary to reach a conclusion. He noted that Polkinghorne told police and the 111 operator on the day of his wife’s death that he had loosened or undone the knot shortly after finding his wife and cutting the other end of the rope.
It makes sense that someone trying to undo a knot would lift it up the bannister for easier access if it had slid down during a hanging, he suggested.
Mansfield also noted that the knots used to secure the rope were relatively simple, while Polkinghorne’s knowledge of complex knots would have been second nature. The defence played animated videos of surgical and simple knots to show jurors the difference.
Adding confusion to the matter, there were actually two ropes found at the scene - another one left in a jumbled mess on the stairs next to Hanna’s body. That might have been the actual rope Hanna used to hang herself before her husband cut it down, Mansfield suggested.
The lawyer noted that, although not in the expert’s report, Chisnall had sent an email to authorities early on noting that the rope on the stairs had some kinks in it that might possibly match the three bannisters upstairs. Chisnall said there wasn’t enough evidence to know for sure, which is why it wasn’t included in his final assessment.
“I thought it was the only piece of rope,” Polkinghorne told police, according to a transcript read aloud by his lawyer. “I didn’t see the other one [still tied at the top of the stairs]. I thought I undid that.”
But everything was flustered as he reacted fast, he continued.
“I’ve never seen that [knot] up at the top, unless I lifted it up to undo it,” he continued to police. “I thought I undid it. I thought I got rid of it. I’m sorry, I can’t help you anymore.”
The Crown is expected to call more witnesses as the trial resumes this afternoon before Justice Graham Lang and the jury.
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.
