There was contamination of a blood-like marking in the home of Philip Polkinghorne in the two years between tests, Crown prosecutors have suggested.
The defence is calling witnesses in the trial of former eye surgeon Polkinghorne, who is accused of murdering his wife Pauline Hanna in April 2021.
United States forensic scientist Dr Timothy Scanlan was tasked by a lawyer for Polkinghorne to conduct independent testing of his Remuera home in 2023, two years after police had conducted their own test.
Dr Scanlan said he found blood belonging to Polkinghorne on a red mark on the garage stairs.
In cross examination, crown prosecutor Brian Dickey asserted that Crown witness Fiona Matheson tested the general area and did not find blood.
But she did not test that exact red mark.
Dickey said the photographs of the blood - taken two years apart - were different.
"I'm talking about the appearance of a second parallel line, on the second photograph, taken by [Dr Scanlan]. That could have come from contamination of the scene, couldn't it?" Dickey questioned.
"Yes, it's a possibility," Dr Scanlan said.
Dickey said cleaning could not account for the change between photographs.
"If his blood is not in the left hand photograph, and yet it's in the right hand photograph, and the right hand shows us a different thing to the left hand, aren't we dealing here with rather obvious scene contamination?"
Investments were not a secret - manager
Meanwhile, Polkinghorne's investment manager said it did not appear that his investments were a secret.
The High Court in Auckland has previously heard evidence from financial analyst Margaret Skilton of two $250,000 payments made by Polkinghorne to JB Were Investments from the Hanna Polkinghorne Trust.
The total investment portfolio was said to be worth more than $2 million.
Tony Glucina - an investment manager with JB Were - said it was common enough to deal with just one person about a couple's investment portfolio.
"I dealt primarily with Philip because the investments were in his name," Glucina said.
Defence lawyer Ron Mansfield KC questioned him on whether the investments were a secret.
"From your dealings with Pauline, although she wasn't the point of contact for the investments, was it generally clear that she was aware that investments had been placed on their behalf with JB Were, albeit in Phillips name?" Mansfield asked.
"Yes, of course," Glucina said.
"And did it appear to you that there was ever any secret about the investment with your your company, your business?"
"No."
"Did Pauline ever contact you out of concern about not knowing what's going on or wanting to know more?"
Glucina said she had not, but he would not have been able to disclose any detail to her if she had, because the investments were in Polkinghorne's name.
He had dinner with the couple in the months before her death, and said she seemed stressed and did not eat.
Other than that, Glucina said there was nothing out of the ordinary.
"How did Philip treat Pauline?" Mansfield asked.
"Like a normal couple. Philip is quite a flamboyant, interesting person to talk to, always cracked in a few jokes," he said.
A dry sense of humour
Two staff members who worked under Polkinghorne also said he was generous and always put his patients first.
Leonie Mary Darlington, a theatre hostess, said Polkinghorne was very particular and a perfectionist.
"Quite a dry sense of humour, he always ready for a laugh," she said.
Ophthalmic nurse Jillian Blakely said Polkinghorne was supportive and happy to teach in her 27 years working with him.
Dominic Foote, a long-time friend of Polkinghorne and Hanna, said he had a neighbouring bach to the couple and they had regularly had dinner.
"He's great. He's kind, generous, fantastic with my kids. A great neighbour," he said.
Foote said he had never seen Polkinghorne raise his voice.
"I don't think I ever saw Philip drunk but he did enjoy taking a comically large glass of wine around," he said.
Mansfield asked if he had ever seen Polkinghorne be controlling or demeaning to Hanna.
Foote said he had not.
