But he did all these things, said Mr King, "all the time carrying this deep, dark terrible secret of his past actions towards the deceased. They were despicable. And he will be punished for them."
Macdonald has admitted trashing the new home of Scott Guy and his wife Kylee with a splitting axe, burning down an older home and stealing deer from a neighbour's property.
But he made the admissions only after police confronted him with a confession from his accomplice, Callum Boe.
"He did not tell the truth about what he did 18 months before his brother-in-law's death," said Mr King. "It's to his eternal shame he did not do that."
But the defence case was that everything else Macdonald told the police was the truth, said Mr King, and that was corroborated by other evidence heard in the four-week trial.
"That he has pleaded guilty to arson and vandalism and stealing deer does not change or alter the fact that he is presumed to be innocent. Innocent unless proven guilty."
To convict him of murder, Mr King said, the jury must be sure of his guilt beyond reasonable doubt.
He promised to talk about the "absolute abundance of doubt in all strands of the Crown case" when he closes the defence argument today after Crown prosecutor Ben Vanderkolk's final address.
Justice Simon France will sum up either tomorrow morning or on Monday, depending on what the jury wants to do.
Mr King called two witnesses yesterday afternoon. The first was electrical engineer Peter Shelton, who measured electro-magnetic fields outside the home of Mr Guy's neighbour, Derek Sharp.
Mr Sharp gave evidence that he woke just before 5am to hear two gunshots. But he could not be precise about the time as he believed his digital clock was inaccurate because he lived under the power lines.
Yesterday, Mr Shelton said the electro-magnetic fields from power lines had no effect on a digital clock.
While Mr Sharp heard two gun blasts, his flatmate Bonnie Fredriksson heard three loud bangs.
Mr King also called a champion shooter Mitchell Maxberry, an American with New Zealand citizenship who lives in Lower Hutt.
The trial was told Mr Maxberry was a qualified gunsmith who had owned 500 firearms in his life and won five national and 50 regional shooting titles in the United States.
He conducted rapid-fire tests with Mr King at a shooting range.
Seven seconds was the fastest time in which he could fire three shots from a double-barrelled shotgun - the same type as the firearm the Crown alleges Macdonald used.
This was because he had to eject the two spent shells and load the third.
But he could fire three shots from a semi-automatic shotgun in 1.5 seconds - as quickly as he could pull the trigger.
Earlier, the Crown's final witness, Environmental Science and Research firearms expert Kevan Walsh, said he believed Mr Guy was shot in the throat from only metres away, then shot again as he fell backwards with his arm raised.
The first shot "almost certainly caused him to drop instantly", said Mr Walsh.
The court had heard earlier evidence from pathologist Dr John Rutherford, who said Mr Guy probably died within seconds from the throat wound.
A plastic wadding, which holds the pellets in a shotgun shell, was found inside the wound.
A second wadding was later found in grass at the crime scene.
Mr Walsh said a second blast, fired as Mr Guy fell backwards, struck his left forearm, face and cap. Other pellets from this shot hit a wooden fence behind him.
By test-firing several firearms - including the 12 gauge double-barrelled shotgun from the Guy farm - Mr Walsh said he could estimate distances from which Mr Guy could have been shot.
He used Winchester Bushman cartridges with number 5 lead shot, which matched the plastic wadding found at the scene. The same Bushman cartridges were found at the Guy family farm.
At best, he said the 12-gauge shotgun from the Guy farm "could not be excluded" as the murder weapon.
Under cross-examination by Mr King, Mr Walsh said there were "probably hundreds of thousands" of shotguns in New Zealand and most would be 12-gauge.
He also agreed that Winchester ammunition was very common.
Mr Walsh said he "could not exclude" the possibility that a third shot was fired, but he had not seen any evidence of that.