Philip Polkinghorne. Photo: RNZ/Nick Monro
A forensic expert says DNA matching Philip Polkinghorne was found on his wife's neck after her death.
The former eye surgeon is on trial at the High Court in Auckland accused of the murder of his wife Pauline Hanna in their Remuera home in April 2021. His defence argues her death was suicide.
Forensic scientist Nicholas Curnow was one of the experts who gathered DNA samples from throughout the house.
He confirmed that the red stains shown on Pauline Hanna's left hand earlier in the trial were blood.
"The sample collected from Ms Hanna's left index and middle fingers... That did have the visual appearance of blood and also gave a positive result in a chemical test for blood," he said.
Alongside a standard test, Curnow said the forensics team used a second method to help identify Polkinghorne's DNA.
"The second type of DNA testing which I used in this case was what's referred to as a 'male specific DNA test' and essentially that looks at only male DNA in a sample," he explained.
Multiple DNA samples were taken from Pauline Hanna's neck.
"The neck samples and the samples collected from her fingers were tested using both types of DNA testing, the standard and the male specific DNA test," he said.
"For the sample collected from the right side of Ms Hanna's neck, DNA from at least three people was detected. Some of the DNA could have originated from Mr Polkinghorne."
Pressed by Polkinghorne's lawyer Ron Mansfield KC, Curnow acknowledged the DNA could have been several days old.
"You can't age the DNA, correct?" Mansfield asked.
"That's correct, that's one of the limitations. We can't say how old that DNA is, no," Curnow replied.
"It could have been there for minutes, hours, days, or even much longer than that?" Mansfield confirmed.
"That's correct."
Crown prosecutor Alysha McClintock asked Curnow if he had tested the meth pipe found under Polkinghorne's bed.
"Yes, that was analysed using the standard DNA test and the results from that sample indicated that the DNA could have originated from Polkinghorne," he said.
The trial continues on Tuesday.