A former detective inspector says a storage unit where human remains appear to have been kept will be the initial focus of the police's investigation into the grisly discovery.
Police are still awaiting post-mortem examination results to identify the human remains found in a suitcase at a Manurewa address in Auckland last week.
It is understood a family had brought home a trailer-load of items, won at an auction for abandoned goods in a storage unit, without realising what was inside.
Lance Burdett worked for the police for 22 years, including as a detective inspector heading the investigation of multiple homicides.
"The storage facility will be the key to this. Hopefully there is some video footage ... or there'll be a paper trail of some sort, so they've got a couple of scenes now where examination can be carried out," he said.
"It's just a methodical process of going through piece by piece and really the key would be information from the public."
Storage unit contents are auctioned off as a last resort when customers abandon goods and stop paying the fees.
TradeMe runs online auctions for storage unit contents but its head of trust and safety Lisa Kerr said they were uncommon with only five current listings.
Burdett said a void of information from police was fuelling speculation.
"At the moment there's a lot of conjecture as to what's happened and the mind wanders off to all sorts of events and possibilities but oftentimes it never is what we think it is," he said.
"As a police officer what they'll be trying to do is keep an open mind. Rather than start coming up with all sorts of scenarios it's about just looking at the facts."
Police would be working hard behind the scenes, Burdett said.
"Every avenue you can think of they'll be doing. Missing persons will be one of the first things they would be doing there but again it depends on whether the person or people have been reported missing."
When he lead homicide investigations, Burdett saw the bodies of victims who had met untimely and violent deaths.
He expressed concern for the family who discovered the human remains.
"It's something that you can never unsee, you can never unsmell. All the senses become heightened and the brain takes all of that information in," he said.
"It's not the greatest of discoveries to make and I just hope the family that did discover it are getting all the care that they need."