A murder suspect allegedly told friends while police were searching for a missing man, “I don’t give a f*** what happened to him”, a court heard today.

Ex-prison guard David Benbow denies killing his friend 49-year-old Michael McGrath on Monday, May 22, 2017 and is standing trial at the High Court in Christchurch.

No body and no gun have ever been found.

Today, the jury has been hearing from friends of Benbow who was a close mate of McGrath before he vanished. McGrath had just entered a relationship with Benbow’s partner of 17 years, and mother to his two children, Jo Green who had walked out two months earlier.

Pamela Barnes, who also lived in Halswell, knew both Benbow and Green.

At a neighbourhood BBQ at her home on Saturday, May 20, 2017 – just two days before Benbow is alleged to have lured McGrath to his home, shot him dead, and disposed of his body – Benbow seemed upset he couldn’t bring the children along, she said.

“David is quite hard to read,” Barnes told the court.

“I wouldn’t say emotional. He was never tearful or anything like that. You could tell he was agitated.”

Barnes and her husband Andrew, also a Corrections officer, later heard that McGrath had gone missing and that Benbow’s Candys Rd property was being searched by police.

After he got his house back, Benbow visited the Barnes’ place, the court heard. Barnes said she had several chats with him.

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

She became uneasy and “a little bit nervous” after things he had said. Asked by Crown prosecutor Claire Boshier, what things, Barnes replied: “A little bit around his demeanour. He didn’t seem to grasp the gravity of the situation he was in.”

“Considering his situation, he was the leading suspect in a significant disappearance, he just didn’t seem like somebody who had a massive life issue going in. He was quite calm and quite matter of fact,” Barnes said.

She added: “He never said, ‘I didn’t do it’.”

When her husband asked Benbow why police had been searching his septic tank and “what on earth [are] they looking for?”, he reportedly said it was probably that Green had told police about an argument where he had allegedly told her that “if she messed around, I would cut her up in pieces and put her in the septic tank”.

“He also said he would bury her in her car where no one would find her. He was giggling about it,” Barnes told the court.

And when Barnes said to Benbow that he must be worried about McGrath, he got “quite animated”.

“‘I don’t give a f*** what happened to him’,” she reported Benbow saying.

“‘It just teaches you not to introduce your partner or wife to another man’.”

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.

Benbow’s legal team has warned the jury that the police had “investigative bias”, with ex-partner Green immediately pointing the finger of blame at him.

The trial, before Justice Jonathan Eaton, continues.