Ex-partner of man accused of murdering Michael McGrath says relationship was toxic, called police after she broke it off

Murder accused David Benbow's ex-partner and mother of his children told the High Court in Christchurch today Benbow was obsessed with money and that he had told the man he is accused of killing she was fat and couldn't cook.

On the fifth day of the murder trial, Joanna Green told the court she had started seeing her partner's childhood friend Michael McGrath after she left Benbow, which is why the Crown says Benbow murdered him.

Green left Benbow just over two months before McGrath went missing. She said Benbow was controlling with money, always grumpy and the relationship was toxic. 

After Green left Benbow, she started a romantic relationship with builder McGrath who was an old-time friend of theirs. 

The Crown alleges it was Benbow's jealousy and rage of their relationship that caused him to murder McGrath, whose body has never been found.

David Benbow.
David Benbow. Photo credit: Newshub.

Green told the court on Friday morning McGrath was a simple, humble man with a good sense of humour. 

"We could talk about anything, we got on really well," she said. 

In contrast, she said her ex-partner of 17 years, Benbow, and father of her two children was obsessed with money when they were together and always grumpy. 

"Our family came second to money, our family came second to work, our family came second to a lot of things," Green said.

She told the jury when her relationship broke down with Benbow, both she and Benbow went to see McGrath to talk about it. 

She also rang the police when she was leaving because she was worried about how Benbow would react. 

Green said her relationship with McGrath turned romantic after she left Benbow but they tried to keep it a secret as she didn't want Benbow to get hurt. She told the court she had propositioned McGrath after she left Benbow. 

"I asked if he would teach me how to kiss and be touched, I trusted him that much," she said.

Their relationship turned intimate shortly after. 

Green got emotional when remembering McGrath, often crying in the witness box. She said he cared about her and her children and all of their welfare. 

"He was a good-looking man and he was very kind. We got on so well. I just wish he was still here," she said.

Green is the 17th witness in the trial where the jury will hear from over 130 witnesses.