Ewen Macdonald's father says there's no way his son could have accessed his guns without his knowledge.
Macdonald is on trial in the high court in Wellington for allegedly shooting dead Scott Guy in July 2010.
Kerry Macdonald has told the court that he has a number of his own guns, which he would often lend to his son.
But he says on the day of Scott Guy's murder Ewen Macdonald didn't have any of his guns and there's no way he could have accessed them.
"I've got two gun safes designed to hold military-style semi-automatics so it's rated to hold pistols and that sort of thing and it's a electronic keypad to get in."
Kerry Macdonald also owns a local hunting store but says he's sure his son hadn't borrowed guns from there either.
Marlene Macdonald says her husband Kerry is a keen hunter and their sons picked up his interest.
"From a very young age, Kerry put a firearm in their hands, just for curiosity's sake and to show them safety of firearms."
Marlene Macdonald says her husband felt it was necessary for the boys to satisfy their curiosity about guns so they didn't play with them.
She also says Ewen Macdonald told her that Scott Guy had had his throat cut when she asked how he died.
The crown claims Macdonald knew Mr Guy had been shot before it was confirmed by police.
Witnesses have also told the court that on the morning of the murder Macdonald corrected people who thought Scott Guy had had his throat slit.
Marlene Macdonald today told Crown Prosecutor Ben Vanderkolk of the night of the murder, and recalled a conversation she had with her son.
"And I said to him, 'do you know how he was killed?' And he said 'I think his throat might have been cut'."
Marlene Macdonald said Ewen Macdonald wasn't sure about that, and didn't explain why he wasn't sure.
Earlier today Ewen Macdonald's wife wavered over evidence she gave about her husband's dive boots.
The crown claims Macdonald wore diving boots with a distinctive pattern on the morning of the murder, but Anna Macdonald has previously told the court that she threw those boots out into a trailer in 2008.
Today she told the court that she couldn't be sure.
"The last recollection I can make is the one dive boot that I saw that we always kept a key in, and I thought it was scungy we were going to move and I said to Ewen we're not keeping it, I think I remember throwing them out but I can't remember physically throwing them out.
"I think it was probably more assumption, because there would've been a trailer at the back door, and that's where we throwing the rubbish. So probably if I thought about it, and ... physically throwing it onto a trailer? It's too long ago, this is four years ago. I can't remember."
Anna Macdonald has also recalled her husband's movements on the morning he's accused of killing Scott Guy.
The crown alleges Macdonald shot Scott Guy at 4.43am before deactivating an alarm at a milking shed at 5am.
But Macdonald's defence says there are issues with timing on that morning, and he's questioning Anna Macdonald closely about it.
Defence lawyer Greg King asked Anna Macdonald: "As best you can recall would his alarm have been set for around about 4.50am that morning."
To which she replied "yes".
Anna Macdonald says she can't remember anything unusual about her husband on the morning of the murder.
Police investigating Scott Guy’s murder have told of the extensive searches they carried out on the Guy family farm.
Detective Gregory Hogan has told the High Court of measures police took following the murder in an attempt to turn up evidence.
"I was searching for deer, remains of deer, deer antlers, ear tags, dive or footwear capable of making an impression, remains of puppies, shotgun, empty cartridges," he says.
Detective Hogan says a number of the farm's effluent ponds couldn't be searched.
Scott Guy's father Bryan gave evidence yesterday about the Feilding property that Ewen and Anna Macdonald had been living on at the time of the murder.
It's expected further evidence about the property will be heard today with Macdonald's parents appearing for the first time.
The court heard emotional evidence yesterday surrounding Macdonald's vandalism attack, with both Kylee Guy and Anna Macdonald outlining how the attacks panicked them.
Anna Macdonald told the court she had no idea her husband was involved in the incidents, until after his arrest.
But she said following his arrest she asked him if he had murdered her brother - and he swore to her he hadn't.
Photo: Ewen Macdonald (NZ Herald)