Texts from an increasingly worried boyfriend led to the discovery of a Wellington woman, killed in her own home.

Michael Preston is on trial in the High Court in Wellington for the murder of his estranged wife Mei Fan almost two years ago.

Witness Matthew Breach said Ms Fan’s boyfriend at the time text him from Vietnam – concerned that he hadn’t heard from her.

He's read the texts in court.

"She may have hurt herself, fell down at stairs, suffered a stroke - anything. Maybe she can't move. Please break in if you can't find key, I am really worried."

Crown lawyers said Preston left forensic evidence linking him to the scene, despite his best attempts not to.

Crown lawyer Emma Light said the knife used to kill Mei Fan had black fibres wrapped around it - consistent with hair from a black wig used by the couple's daughter for Halloween two years earlier.

"When interviewed by police about where that hat was, she said it was at her dad's. That hat, with a black wig attached was never located during searches of the defendant's address."

The Crown alleges Preston used the wig as a disguise to get into Mei Fan's home, and that Michael Preston killed his estranged wife to gain custody of their children.

Crown lawyer Emma Light's told the High Court in Wellington Ms Fan died during a frenzied knife attack. 

"In which she sustained 15 knife wounds to her neck area. She also sustained multiple defensive wounds to her hands."

Emma Light said there's no question Mei Fan was murdered, but jurors must decide if Michael Preston is responsible for her death.

 Ms Light's told the High Court in Wellington the couple’s 10 year relationship was at times fractious.

"Interspersed with acts of violence in China, and efforts on the defendant's part to undermine Ms Fan's relationship with their children."

Emma Light said Michael Preston had attempted to have Chinese national Mei Fan removed from the country, so he could gain full custody of their two children.