The mother of 21-year-old Brendon Hamilton says her son's girlfriend frequently hit and swore at him.
Rikki-Lee Simeon has denied murdering her partner Hamilton, who died after being stabbed in the neck at the couple's Dominion Rd flat on May 18, 2019.
The young parents had a baby daughter who turned 1 year old on the day Hamilton died.
The High Court in Auckland heard Hamilton admitted being violent to his girlfriend once, but only when he said she'd tried stopping him from leaving their house.
On Monday afternoon, Hamilton's mum Adoniah Lorigan told jurors of the last time she spoke with her son on the phone.
Lorigan said her son told her: "Mum, I love you. Tell the family I'm sorry I can't be there for the baby."
Lorigan, who was looking after the child in Rotorua, described a tempestuous relationship and said she'd long had concerns about the couple.
Jurors heard the couple started going out when Brendon was 17.
"I said: Brendon, you can't go out with this girl because she's only 14 and you'll get yourself into trouble."
"When she was fighting with Brendon she would always hit him, push him," Lorigan added.
The court heard Lorigan applied for a parenting order in December 2018 and on the 16th of that month she trespassed her son and Simeon from her property.
"Rikki came over for a supervised visit and all she did was fight with Brendon."
"The supervised visit was for an hour. She didn't leave my house for five days."
Lorigan said her son did not slap or push his girlfriend.
The murder trial also heard Hamilton said he would ensure Simeon's family stayed away from Lorigan's house.
After a Mt Roskill house party, Hamilton was killed at a Mt Eden apartment a tenant was sub-letting to the young couple.
The court heard Hamilton was at times estranged from both Lorigan and from his father, Brent Hamilton.
The father told jurors the young couple stayed with him for about six months in Glen Innes, where he'd occasionally hear fighting.
"But I'd knock on the door and my son would say: Yeah, we're all right."
The father told jurors his son and Simeon would then settle down, but the shouting episodes happened about once a week.
The court heard Brent Hamilton at one point urged his son to leave the relationship but his son told him not to interfere.
The arguing led the father to eventually ask the couple to leave.
He said his son and the girlfriend both argued, and though Simeon did most of the yelling, both caused damage.
"I'd come home and there'd be holes in the wall."
The trial was told the last time the father and son spoke, Brendon spoke of moving in with his dad.
But Brent Hamilton said his son proved hard to get in touch with in the weeks before his death.
"I just wanted to see if my boy's all right, you know."
Jurors were read an affidavit Brendon Hamilton signed on August 20, 2018.
"Rikki is all over the place. Her moods are up and down and she can be violent."
He said his girlfriend could be jealous and possessive.
"She accuses of me of playing around, which isn't true."
He said he needed Lorigan's help to care for the baby but also didn't want Simeon to be stopped from seeing the young child.
He said he wanted a better life for their daughter, and Simeon had agreed.
Hamilton in his affidavit said he struck Simeon in the cheek once and ran away.
"I was trying to leave my house ... and she wouldn't let me go."
Prosecutor Kirsten Lummis then closed the Crown case.
Defence counsel Paul Borich QC previously urged jurors to avoid demonising Simeon for relationship problems.
The trial before Justice Neil Campbell continues.