Two rural posties found notes in Scott and Kylee Guy's letterbox about the time an old farmhouse was destroyed by fire and their new house was vandalised.

Brett Macdonald, who is no relation to murder-accused Ewen Macdonald, and Emma Beaney delivered the mail in 2008/9 down Aorangi Rd where the Guys lived.

On October 24, 2008, an old house waiting to be removed from the Guys' part of the family farm at 293 Aorangi Rd was torched.

And overnight on January 30, 2009, the Guys' new house at that address was vandalised and offensive graffiti was tagged to the outside.

Ewen Macdonald and former farm worker Callum Boe have admitted those crimes but Macdonald says he knows nothing about malicious notes sent to the Guys when they were still living at 259 Aorangi Rd.

Their letterbox was next to an identical one. Neither had a name on it.

In the High Court at Wellington yesterday, on day 13 of Ewen Macdonald's murder trial, Kylee Guy said she did not see the notes and had no knowledge of them.

Macdonald, 32, is accused of gunning down Mr Guy on July 8, 2010.

The defence says Macdonald is not the killer.Ms Beaney first found a note after the fire and after she had an accident in November.

"It was just on plain paper, there were no lines on it. It was in big writing; it was bold," Ms Beaney said. "It said: Stay away from him Kylee, you whore."

She said she read the note as often people would leave messages about their mail.

Another similar looking note, left after after the vandalism, said: "Now you know how it feels to lose something you love."

Ms Beaney did not tell the Guys about the notes.

She did, however, tell Aorangi Rd resident Alison Rankin about one of them, and Brett Macdonald, who was her boss.

"I mentioned to Brett we should let the police know and he said: no, it's not our business."

Only after Mr Guy's murder did Mr Macdonald tell her he had also found a note.

He told the court he discovered it one Saturday morning and, like Ms Beaney, picked it up in case it was meant for him. It was written in pen on a scrap piece of paper.

"It said something along the lines of: You cheating whore; and, What comes around goes around."

Mr Macdonald said he didn't tell anyone at the time as he didn't want people to think he was "nosey".

Defence lawyer Greg King asked Mr Macdonald why he now thought he saw the note after the arson, when he had previously told police he was 60 to 70 per cent sure he found it before the blaze.

Why had he changed his mind?

"I'm not sure," Mr Macdonald said. He said he did not think the note was meant for him, although the reason for Mr King asking him that was suppressed by Justice France.

Mr King asked Ms Beaney if the two notes even existed. "There were definitely notes," she said.

- © Fairfax NZ News