Murder accused Wilson Apatu left the home of the man he allegedly shot and killed yelling "I didn't mean to, I didn't mean to", a court has heard.
Wilson Neil Apatu, 40, is on trial for murdering Layden Rameka, the attempted murder of his son and entering a building with intent to commit homicide.
Mr Rameka died after being shot four times in his Waikoau home on August 30 last year.
On the first day of the trial the court heard how a dispute between Apatu and Rameka about the behaviour of Rameka's boys in relation to car keys had led to a physical altercation.
The crown alleges Apatu, just hours later, returned dressed in hunting clothing with a SKS 7.62 semi-automatic rifle and shot Rameka before fleeing the small old-railway town.
Rameka's partner of 17 years and mother of their six children Janine West, her cousin Annjalah Fuentez, and two of the couple's children who were 13 and 8 at the time were yesterday called as witnesses in the trial at High Court in Napier. All witnesses were in the room when Apatu allegedly shot Mr Rameka. The court heard how Mr Rameka had seen Apatu coming up the driveway with the rifle and had rushed inside the house, yelling at everyone to get into Annjalah's bedroom.
Mr Rameka was the last into the room and tried to block the door with a chest of drawers.
Ms Fuentez told the court Mr Rameka had "grabbed the rifle thing when Wilson had put it through the door and that's when I heard the four gunshots".
Ms West said Apatu "had a smile on his face" as he fired his fourth and final shot.
Defence counsel Russell Fairbrother painted a picture of a man with mental health problems who had been taunted by Rameka's children and could not mentally deal the with fight with Mr Rameka.
During defence's cross examination the two children admitted to stealing from Apatu and would often come and go from his house at will.
They would steal items from his house including walkie talkies, spray cans and a car despite his ongoing pleas to "go home, stay home and to not come back".
Mr Fairbrother put it to the couple's eldest child, now 14, that he "thought it quite fun to terrorise a person you thought had half a brain".
Ms West said she was aware of Apatu's mental health problems and had caught her oldest child joy riding in one of Apatu's car days before the fatal shooting.
The trial is expected to take two weeks.