Her body was badly decomposed, meaning her cause of death was never conclusively determined.
But police are clear on one thing - Matsuzawa's death was the result of the actions of another person.
More than 21 years on her death remains a mystery.
In episode three of Herald podcast A Moment in Crime, we look into Matsuzawa's death and speak to the officer in charge, and another who worked on the case two decades ago.
We revisit the theories and suspects, the facts and the speculation and tell Matsuzawa's story in a bid to unearth new leads for police.
Operation Net - the investigation into Matsuzawa's death - is being overseen by Detective Inspector Scott Beard.
He was also the lead police officer in the Grace Millane murder investigation.
Millane was killed last December on the weekend of her 22nd birthday.
Last month a man was found guilty of her murder.
He met Millane on the dating app Tinder and, after taking her to several Auckland bars, killed her in his Queen St apartment, put her body in a cheap suitcase and buried her in a shallow grave in the Waitākere Ranges.
Millane's parents were in New Zealand for the entirety of the murder trial in the High Court at Auckland.
Unlike the Matsuzawa family, the Millanes have answers.
The Japanese family are still waiting for justice, and today we hope the podcast encourages anyone with information to come forward and put this case to rest.
A Moment In Crime is written and hosted by Anna Leask, senior crime reporter for the Herald. The podcast is produced by Chris Tarpey and Frances Cook is the executive producer.
Leask has been covering crime and justice for the Herald for more than a decade and has reported on most of the major incidents and events over that time.
"Each month I'll take you inside some of our most infamous incidents, notorious offenders and behind the scenes of high profile trials and events to show you what's really happening in your backyard," she said.
"Heroes and villains battle for justice to be done, and it seems no matter how horrifying the story, we always want to know more.
"If you want to know more about the cases that have shocked and shaped our nation - from murders and massacres to violent villains and the utterly unbelievable - join me for A Moment In Crime."
In our first episode we looked back at the Christchurch terror attack - what unfolded on March 15 and how it changed New Zealand.
Despite exhaustive and repeated searches, there has never been any sign of the little girl.
To mark the 25th anniversary of Amber-Lee's disappearance, Leask investigated the famous cold case in a bid to generate some answers for the toddler's family.
It was the Herald's first true-crime podcast.
You can listen to A Moment In Crime on the Herald website now, or download episodes on iHeartRadio, Google Podcasts, Spotify or Apple Podcasts next week.
We want to hear from you
If there's a case you want us to consider covering, email