A man has been charged with the murder of Auckland couple Elizabeth and Herman Bangera.
The pair were stabbed to death in their Epsom home on The Drive, on Friday.
Emergency services rushed to the property at about 11.30am, but the husband and wife died despite paramedics' best attempts to save them.
Another person who was hospitalised with superficial injuries has been discharged and interviewed by detectives.
The Herald understands this person may have been a passerby who tried to intervene.
A 29-year-old faces two charges of murder and one of attempted murder.
He remains under police guard at Auckland Hospital.
A bedside court hearing is scheduled for tomorrow.
Police say they have been in regular contact with the couple's family through Victim Support during this "extremely difficult time".
"This is an absolutely tragedy for this family, their friends and wider community," detective inspector Scott Beard said.
Beard has described the killings as "a tragedy" and a "family harm incident".
Pamela Brooking, former director of Child Evangelism Fellowship, who knew the couple well, described Herman, 60, as a "lovely man and wonderful dad" and the family as the "epitome of what family is".
Brooking said Herman was a volunteer at the organisation for a period of time since about 2011 when it had its headquarters in Penrose.
AUT lecturer Ranjana Gupta earlier told the Herald she was shocked to learn her former neighbours were both dead.
"Who would kill them? I cannot understand that. There has to be some kind of motive behind the killing."
Elizabeth Bangera, 55, worked at the University of Auckland.
A spokesperson said the university is "shocked and saddened".
"Elizabeth has been part of our university community for many years, working as a group services co-ordinator in the School of Pharmacy, Faculty of Medical and Health Sciences.
"She was a highly respected colleague and friend."
The spokeswoman said support and trauma counselling was being offered to anyone in the university who may have been affected by the incident.
The couple immigrated to New Zealand from the Indian state of Goa and moved into the block of flats around 2007 because it was in zone for Auckland Grammar where their son attended, Gupta said.
His actions have been described as a 'veritable crusade' against a fellow practitioner.