Waikato Detective Senior Sergeant Stephen Ambler said a post-mortem examination confirmed it appeared she died from a non-violent death.
"She had no injuries. There's been no violence in relation to her death, not a single injury on her body recorded. There's no apparent reason for her to die."
Ambler today said police were still investigating her death, gathering statements from friends and family.
Her parents, Dean and Tracey, run Mana Tangata Boxing Club in Hamilton.
She was also a qualified embalmer and funeral director and had worked at Hamilton's Simplicity Bereavement Services for two years, leaving six months ago.
A manager for the company said Northover continued to pop in and see the staff.