Police have named the two people who died in a double homicide in the Auckland suburb of Epsom on Friday.
They were husband and wife Herman Bangera, 60, and Elizabeth Bangera, 55. They were stabbed and later died in a home on The Drive just after 11:30am.
A third person, believed to be their son, was taken to hospital with critical injuries.
On Sunday, Detective Inspector Scott Beard of Auckland City Police confirmed it was a family harm-related incident.
"A man, who is related to the couple, is still in a critical but stable condition in Auckland Hospital," he said.
"He remains under police guard and at this stage police are not seeking anyone else in connection to this incident."
The man will be interviewed by police when his condition allows. No charges have been laid at this stage.
A fourth person related to the incident was also taken to hospital on Friday. They were a close family friend who had been called to the house just before the incident happened. Det Insp Beard says they suffered superficial injuries and are in shock.
A scene examination is ongoing and the investigation team is continuing to speak to people linked to the family.
"Police wish to thank those members of the public who have provided information to assist," Det Insp Beard says.
"Our thoughts and sympathies are with the families and friends of those involved in this tragic incident."