The Crown alleges Prasad broke into Ali's home and waited for him before attacking him with a hammer and a knife when he arrived.
Nalini Roy said she was talking to Ali on the phone as he arrived home after work on February 21, 2021. "I heard yelling and screaming, and asked what's going on. I thought he had put on the TV."
She heard three or four screams - but no words - before she threw the phone on her bed. She went to her son's room and told him there was something wrong and they needed to go to help. She called a family member to ask them to help and call the police.
They drove the five-minute trip to Ali's apartment, not stopping for the traffic lights. The main door was locked but she went to the sliding door. The curtain was closed but she could see a gloved hand holding the door. "It was full of blood," she told the trial.
Her son then told her they were too late and it was too dangerous, and they drove to the police station.
Nalini Roy said she had married Prasad when she was 19, in Fiji, and they later came to live in Christchurch where she worked as a caregiver. She told the court she was "not really happy" in her marriage.
She met Faiz Ali in 2014 at the shop where he worked as the manager, and they became close. Ali's wife had gone back to Fiji by then.
They began a relationship in 2017, and her own marriage ended in 2020. She and Ali were planning to move in together.
After the separation, she "blocked" Prasad in whichever way she could, but he still tried to contact her through family. "He wanted to talk to me for the last time and explain things, but I didn't want it," she said.
Her car was damaged twice, and her phone and other items were stolen from her bag at a sports ground. Her papers and jewellery went missing from her house. The day before the homicide, she saw Prasad outside Ali's apartment, taking photographs of her car parked there. After that, Ali picked up the papers from the police to issue a trespass notice.
Ravnil Roy, the cousin of Nalini Roy, told of Prasad moving in to his household when the couple separated in 2020. He was upset and wanted to reconcile with Nalini Roy. At one stage, Prasad said: "If I am going to do something, I will do something big." After the incident in which Ali was killed, Ravnil Roy noticed that the filleting knife from his home was missing. He identified the knife in photographs in court.
Barnaby Hawes and John Whitcombe appear for the Crown; James Rapley QC and Ben Walker appear for Prasad. The trial, before Justice Rob Osborne and a jury, is expected to take up to two weeks.
The trial is continuing.