Three years to the week before Auckland businesswoman Elizabeth Zhong was found murdered - her body wrapped in blankets in the boot of her own Land Rover - she had engaged in an hours-long argument with her ex-husband, which resulted in his arrest.

The fight, in the same bedroom where the on-again-off-again couple sometimes shared a bed and where Zhong would later be stabbed more than 20 times, was over whether Zhong was being unfaithful with business partner Fang Sun, ex-husband Frank Fu told jurors today.

"Elizabeth and I were discussing whether she was ... sleeping with Sun Fang on the third floor," Fu said, explaining that they also argued some about business troubles.

"She was not pleased. I was a little over-agitated."

The day after the fight, Zhong applied to trespass him from the Sunnyhills home where they were both living at the time and from three of her businesses. Police came to the house as he was playing the piano and took him to jail, charging him with threatening to kill.

Those charges were later dropped at a Manukau District Court hearing in 2019.

The current murder trial, which has been ongoing in the High Court at Auckland for the past two weeks, is for Sun.

Auckland businesswoman Elizabeth Zhong, 55, was found dead in the boot of her Land Rover in November 2020. Photo / Supplied

Crown prosecutors have said Sun was furious, threatening to kill Zhong multiple times over the course of years, because he believed she had caused him and his family to lose more than $25 million in investments through businesses they owned together.

They have alleged it was Sun who broke into her home on the night of November 27, 2020 and attacked her in her bedroom, nearly decapitating her before stuffing her body into a suitcase and then into the boot of her Land Rover. Police found the body inside the vehicle, which was parked on the side of the road in the neighbourhood where both Zhong and Sun lived, the next afternoon.

Testifying today, Fu said his argument with Zhong occurred on 23 November 2017 - a date he remembers well because the next day resulted in his arrest and his last day living at the address.

He remarried in 2018 and in May 2019, after about seven or eight court appearances, the charge against him was dropped. He and Zhong still stayed in touch, sharing custody of their two dogs. But because of his new marriage and her trespass order, he stayed away from the East Auckland home he once shared with her, he said.

However, one day in May 2020, six months before Zhong's death, he briefly dropped by her home to drop off the dogs followed by a meeting at a nearby cafe with the defendant. Zhong did not know about the meeting with Sun, he said.

"I heard he and Elizabeth were in a court fight. I wanted to be in the middle and mediate," he explained.

Fang Sun appears at Manukau District Court in February 2021, charged with Elizabeth Zhong's murder. Photo / Alex Burton

During the meeting, he said, Sun complained that Zhong had transferred money from the businesses to her boyfriend, David Zheng. Fu said he offered advice to Sun about how to resolve the issue but Sun did not react well.

"He said, 'If you do not pay me the shares I will kill your family,'" Fu testified. "I said, 'You wouldn't do such a thing.'"

Earlier in the day, as Fu first took the witness stand, he described immigrating to New Zealand with Zhong and their then 8-year-old daughter in 1997 and how he and Zhong started their lives over - setting up a business school before Zhong got into other business ventures.

He wept, pausing for a long break to wipe tears from his eyes, when asked about the birth of their daughter.

He first met the defendant through his wife, he said, adding that Sun decided to go into business with Zhong after realising they both came from the same region in China and the intermingling of their birthdays was lucky. He and Sun were both born in the year of the cow, while Zhong's sign was a snake.

"In China, a snake animal and a cow animal sign are both considered lucky together," he explained.

The trial got off to a late start today after one of the 12 jurors reported being a household contact of a Covid-19 case.

"As you can see, we are one down," Justice Neil Campbell told the group as they filed into the courtroom, explaining that the juror had tested negative but was showing symptoms. "And so in these circumstances, I have no option but to have him stay home. I've decided to discharge him from the jury."

Crown prosecutor Gareth Kayes and defence lawyer Sam Wimsett agreed to continue the trial with only 11 jurors.