David Benbow was on a dating website one month after his long-time partner left him, and just weeks before he allegedly murdered her new man, a court heard today.

The murder trial of former Corrections officer David Benbow, 54, who denies killing builder Michael McGrath, has entered its second week at the High Court in Christchurch.

His body has never been found – and nor has a murder weapon - despite widespread searches of properties, rivers, waterways, and the city dump since he disappeared on May 22, 2017.

The Crown alleges that Benbow lured McGrath to his semi-rural lifestyle property in Halswell on Monday, May 22, 2017, and used his .22 semi-automatic rifle, with suppressor and sub-sonic ammunition, to shoot him dead and then dispose of his body, just weeks after learning he was seeing his ex-partner Joanna Green and telling a counsellor he wanted to “annihilate” him.

Benbow’s defence team has warned the jury that the police had “investigative bias” and “tunnel vision” from early in its investigations.

Today, through a long line of questioning of Green, Benbow’s lawyers cross-examined her earlier claims that he had controlled her with money throughout much of their 17-year relationship.

On Friday, Green told the court how Benbow had allegedly looked after all of the finances and bank accounts, saying he’d been obsessed with property and money.

She claimed she’d left a “toxic” relationship where “our family came second to money”.

But she agreed, after questions from defence counsel Kathy Basire, that all three of the couple’s properties, including two rentals, had been jointly held, and that while she was working part-time, or raising their kids, he paid for most things, and that he supported her financially when she retrained as a nurse.

Christchurch builder Michael Craig McGrath, 49, was last seen at his home in Halswell, Christchurch, in May 2017.

The lawyer suggested that Green, nor the children, were ever left wanting.

Basire put it to Green that she was a strong, intelligent woman and if she wanted to, she could have been more involved in the family finances - something she denied.

Green claimed that Benbow would transfer money around bank accounts without her knowing.

“I never dealt with the money – David dealt with all the transactions,” Green said.

“He refused to give me the password to his computer,” she further alleged, adding that she didn’t know bank account details either.

Weeks after leaving the relationship, her lawyer wrote to Benbow that $179,000 and $20,000 had been withdrawn from bank accounts and needed to be accounted for.

Later, the court heard, Benbow transferred $89,500 into Green’s bank account.

“Your characterisation of him over the control of not only the bank account but the emails is incorrect, because you did have access, after you separated, to a joint email account,” Basire alleged. Green denied that claim.

The trial is ongoing at the High Court in Christchurch. Photo / Pool

After Green left Benbow on March 3 – which McGrath helped her do - she still had email access on her phone, Basire alleged – something she also denied.

But if she didn’t have email access – with Benbow withholding passwords – the lawyer asked how it was that she was able to tell police that Benbow had been on a dating website four weeks after they separated?

“Yes, because the emails came up on my phone to him,” she said.

“I don’t know how the emails got onto my phone because I’d set up a new email only for me ... finally an email for myself.”

Basire asked Green: “Mr Benbow did not control you by the bank accounts or email did he?”

“He did,” she replied.

While the Crown accepts there is no body, no murder weapon, and little forensic evidence in the case, it says there is a strong circumstantial case consisting of many threads that, when taken together, show Benbow is guilty of McGrath’s murder beyond reasonable doubt.

Lead defence counsel Marc Corlett, KC, earlier said that “within hours” of McGrath’s disappearance, Green had pointed the finger of blame at Benbow “and the police duly obliged”.

The trial, before Justice Jonathan Eaton, continues.