KEY POINTS:
The former partner of murder accused Chris Kahui says she was the dominant one in their relationship and that she was sometimes violent with him.
Macsyna King, 31, was giving evidence at Kahui's murder trial in the High Court at Auckland yesterday.
Kahui is alleged to have killed twins Chris and Cru Kahui by squeezing them tightly then slamming them against a hard surface. He denies the charges and his lawyer says someone else - probably Ms King - caused the babies' injuries some time before the Crown believes they happened.
Ms King said she was the dominant one in the relationship.
"I would yell the loudest, I would swear at him and I wouldn't stop until I got what I wanted, to be honest."
The pair argued when she said she wanted to leave Kahui's father's house to live in their own place, but Kahui did not want to leave.
She said the arguments only got physical when she did. "I would yell and swear at him and kick him in the shins and once I slapped his face."
Kahui, she said, was quiet and a gentle, loving father - but he could still "lose it".
Ms King said she told Kahui she needed some time out and left the house on June 11, the day before the Crown alleges the babies were assaulted. She ended up at Kahui's father's place. An angry Kahui arrived later that night to demand she came home.
"I told him to piss off ... that I'd come home when I wanted to."
He was very angry and slammed the door when he left, she said.
She returned home the next morning and told him she would spend that night at her sister's. They argued again but she left, checking the babies before she went.
She said they looked normal.
But when she returned the next morning, her brother, who was staying at the house, said that baby Cru had stopped breathing and that CPR had been performed on him.
"While he was telling me, I put my head down and felt their breath on my face and watched their chests rising. They were still asleep."
When Kahui came home, she demanded to know what happened. Kahui allegedly told her that she should have been at home.
"I understood that [to mean] if I had have stayed there I would have known what happened."
Kahui told her that a fresh bruise on baby Chris' cheek was caused by his 1-year-old brother who had crawled into the nursery and "got at" Chris. She said she accepted the explanation at the time but wanted the babies seen to.
Ms King decided to take the babies to the doctor, stopping at a McDonald's restaurant on the way.
When she arrived at the GP's, the doctor examined the babies in their car seats and she could see him becoming concerned. She was told the babies needed to be taken to Middlemore Hospital immediately.
Ms King will continue her evidence today.
