A devastated husband says he has no idea how his wife died at their Christchurch apartment.
Emergency services arrived at the Selwyn St home about 9.10am on Monday to find Tina Sharma, 28, dead in a hallway, with her husband performing CPR on her.
Police were treating Sharma's death as "unexplained", Detective Senior Sergeant Greg Cottam said.
An autopsy was carried out, but the cause was "still undetermined" and police were waiting on other medical results, Cottam said.
Sharma's husband, who declined to be named, told Stuff on Thursday he did not know what caused his "amazing" wife's death.
He arrived home from work about 11pm on Sunday and helped his wife cook. He then listened to music while drinking beer as his wife lay on the couch.
"It was raining so I put a blanket on top of her, I turned the heater on, closed the window and we just talked about family stuff."
His wife eventually fell asleep.
When he woke about 4am or 5am and tried to wake his wife up, but had no luck.
"She was a deep sleeper, I didn't want to interrupt her."
He tried again at 8.45am.
"I thought she was just playing a game, she didn't want to get up."
He decided to carry her down the stairs.
"I just fumbled on the last couple of steps and she fell on the hallway.
"Then I looked at her face and her lips had gone blueish [and] her nails were blue."
The couple, who have been together for two years, married in January this year. Sharma recently started living in New Zealand.
Neighbours said they heard the couple argue for several hours on Monday morning, but the husband said that was not true. He believed it was the music that the neighbours heard.
"There was no arguments. I know for a fact that I would never lay a hand on her and I would never let anyone do that to her as well."
"I want to know why my wife died just in her sleep."
Police completed a "routine" scene examination at the apartment on Wednesday, Cottam said.
"We are working closely with Ms Sharma's family who are being supported by Victim Support and the local Indian community," he said.