There's "strong scientific support" to suggest that DNA found under the left-hand fingernails of slain Auckland businesswoman Elizabeth Zhong belonged to estranged business partner Fang Sun, a forensic scientist told jurors today.
Zhong's nails were clipped and examined for DNA after she was found stabbed to death in the boot of her Land Rover in November 2020. Sun, who has been on trial for the past five weeks in the High Court at Auckland, is charged with her brutal murder.
DNA analyst Donna Foskin told jurors today that it's 670 times more likely the male DNA found under Zhong's fingernails originated from Sun rather than from another man selected at random from the New Zealand population.
However, a standard DNA test yielded no results other than Zhong's own DNA, so Foskin said she instead relied on a "male-specific Y-chromosome test", also known as a YSTR test, which "effectively ignores any female DNA that is present". That test cannot rule out any paternal relatives, meaning the DNA could have also belonged to Sun's father, son or brothers.
The defendant's father and brother have never been to New Zealand, the defence and prosecutors have agreed.
Foskin said she could determine with certainty that the DNA found under Zhong's fingernails did not belong to multiple other men who have testified so far in the trial, including Zhong's friend Matthew Pickering and her ex-husband Frank Fu. It also excluded her ex-boyfriend David Zheng, who the defence suggested during cross-examination might have been the real killer.
Prosecutors have suggested Sun broke into Zhong's home some time in the night between November 27 and 28, 2020, and confronted her in her bedroom. His rage had been growing for over a year as their joint businesses faltered and he blamed her for losing him and his family over $25 million, prosecutor Gareth Kayes said during his opening statement.
Sun is alleged to have stabbed Zhong over 20 times before stuffing her body in a suitcase, using it to move her body from her bedroom to her garage. Her blood-smeared SUV was found on the side of the road the following afternoon in the East Auckland neighbourhood where both Sun and Zhong lived.
A crime scene analysis expert specialising in blood told jurors today that blood patterns discovered inside Zhong's home were consistent with the wheels of a suitcase being pulled through a pool of blood. Fiona Matheson also suggested, based on her analysis of the blood, how Zhong's body might have been positioned in the suitcase.
Blood pattern evidence also suggests someone spent time trying to clean up at the house after Zhong's death, she said, pointing out that multiple areas appeared to have "dilute" bloodstains - some of which weren't "immediately obvious" until enhancement techniques were used.
A mop with a green handle was found near the entrance to the garage, and stains by one of the home's bathrooms seemed to be created with a circular movement, Matheson said.
"I considered that the object that may have created that pattern was a mop with strings," she explained.
Matheson also described bloody shoeprints in the foyer and the kitchen of Zhong's house. They had a linear pattern and an outline of a heel, "suggesting ... a business-style shoe as opposed to a sports-style or gym shoe", she said.