Three weeks before she was fatally stabbed, Mei Fan's estranged husband and murder-accused was complaining to police she had come into the country on a false passport.
And he was emailing an officer following up the complaint as the same officer attended the murder scene just minutes after Ms Fan's body was found, the High Court at Wellington was told today.
Michael Preston, 60, is on trial, accused of murdering his Chinese-born wife on November 8, 2013 and breaching a protection order by assaulting her.
The Crown says he stabbed her 15 times in the neck at her Miramar flat after failing to get her deported so he could get sole custody of their two school-aged children.
Sergeant Daniel Hughes today told the court Preston had gone in to Wellington police station on October 21 to complain his wife had lied about her birth date on her Chinese passport and had fraudulently used that to get a New Zealand driver's licence.
Preston presented a copy of Ms Fan's Facebook profile with a different birthdate as his evidence.
Sgt Hughes said he never got a chance to follow up the complaint and it wasn't until Sunday, November 10, when he was called to the homicide scene in Miramar, that he noticed he had received a follow up email on his iPhone from Preston, asking about his complaint.
The email arrived less than 30 minutes after police realised they were probably dealing with a homicide.
Officers also gave evidence about Preston's reaction when he was arrested later on the Sunday for breaching a protection order.
Sgt Hughes said the accused appeared "mildly perplexed" by the presence of armed officers.
Constable Oliver Crellin said Preston lost control of himself when he was told there had been an incident at Ms Fan's flat, despite no mention of her death.
The trial is continuing.