There was no way Anna Macdonald was going to visit husband Ewen in jail and not ask the most important question on her mind: did he murder her brother, Scott Guy?

"He said: no, I swear I didn't," she told the High Court at Wellington yesterday.

And it was not just the murder of her older brother in July 2010 that Mrs Macdonald wanted to get her head around.

There was the arson of an old farmhouse on Mr Guy's rural Feilding property in October 2008 and the vandalism of his new house three months later.

Macdonald admitted both crimes shortly before his arrest last April and will be sentenced after his murder trial.

"I had a lot of questions and it wasn't just one visit – it took visit after visit after visit for me to understand what went wrong," Mrs Macdonald said.

She asked her husband why he took an axe to his brother-in-law's half-built home in January 2009, damaging walls, windows and plumbing, and painting offensive graffiti on the outside.

He replied that he was "pissed off" at Mr Guy's wife, Kylee, because Mr Guy would leave the farm he and Macdonald co-managed whenever she called him, Mrs Macdonald said.

She also wanted to know why her husband did not feel he could confide his true feelings in her.

"I just thought, between a husband and wife, that's what you do," Mrs Macdonald said. "He said he wanted to keep me out of it ...

"It was my family and he knew I would be really hurt and [he] didn't want to involve me."

She told the court the vandalism made her feel nervous at the time. "I was freaked out that someone was going to come to our house and do something to us."

Her husband did his best to reassure her, saying it was probably teenagers mucking around.

It was about this time Mrs Macdonald noticed her husband start to warm towards Kylee. He bought her a silk tree for her birthday and got a local kaumatua to bless her new house. But it turned out that was just Ewen feeling guilty and wanting to make up for what he had done, Mrs Macdonald said.

Mr Guy's father, Bryan, said Kylee Guy was very distressed about the damage to her house and at one stage did not want to continue building it.

But Scott Guy managed to reassure his wife that the house was safe by installing sensor lights in the driveway, which were connected to an alarm, Mr Guy said.

Kylee Guy told the court she was so upset at how "violent" the damage to her home was, that it put her off moving in.

"I was just shocked. I just couldn't understand any of it.

"I felt so violated," she said.

"Deep down, I knew I hadn't done anything, so I knew those words couldn't be directed towards me, which was why it was so scary."

Mrs Guy said police installed a secret camera in the house after the damage. One day, the camera showed a four-wheel bike outside the gates of the house, but the rider just sat on the bike.

She was also asked about three abusive notes allegedly put in her letterbox at the time of the vandalism, but she said she did not learn about them until after her husband's death.

The jury had earlier heard evidence from rural posties Brett MacDonald and Emma Beaney, who said they saw the crudely written notes, which appeared to be aimed at Mrs Guy.

Defence lawyer Greg King suggested to Ms Beaney that she was lying about their existence, which she denied.

THE CASE

Ewen Kerry Macdonald, 32, is accused of murdering his brother-in-law, Scott Guy, 31, outside his rural home in Aorangi Rd, Feilding, on July 8, 2010.

The Crown says Macdonald shot Mr Guy twice, at close range, with a double-barrelled shotgun at 4.43am, then rode a bicycle about 1.4 kilometres down the road to Byreburn farm, where he and Mr Guy were expected for milking.

Macdonald has admitted setting fire to an old farmhouse on Mr Guy's property in October 2008, damaging his house with an axe and painting offensive graffiti on its walls in January 2009, but denies murder.

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