Where is Mona Blades? Tune in for the Cold Case premiere to see if you can help bring her family closure.
A fresh look into the police investigation of the Mona Blades case has turned the case on its head and suggested crucial evidence could have been overlooked.
The new investigation forms part of a television documentary series called Cold Case, with the first episode on Mona Blades screening Sunday night.
The Mona Blades case is one of New Zealand's highest profile cold cases.
The 18-year-old vanished while hitch-hiking from Hamilton to Hastings for her nephew's birthday in 1975.
There was a sighting by a truck driver of woman fitting her description getting into an orange Datsun in Taupo and then travelling on the Napier-Taupo Road.
Mona Blades disappeared while hitch-hiking on the Napier-Taupo highway in 1975.
Her disappearance sparked one of the country's largest manhunts with more than 500 suspects who either owned or had driven orange Datsuns investigated.
However, not one piece of evidence or her body was ever found.
Mona Blades disappeared while hitch-hiking on the Napier-Taupo highway in 1975.
Series producer Carolyn Harper, from Screentime NZ, said Rotorua-based Detective Inspector Mark Loper had led a team taking a new look at the investigation.
"We go through the file and find sightings that were previously ignored or not given too much weight as well as statements of evidence that were perhaps overlooked or not given the weight they deserved. The results produce a completely different scenario."
Although she couldn't reveal too much of what the programme concluded, she said one of the aspects they looked at was the photo of Blades that was widely circulated at the time and used to help find her.
Mona Blades disappeared while hitch-hiking on the Napier-Taupo highway in 1975.
She said the photo was taken of Blades when she was a bridesmaid and many had said it wasn't a true likeness, which could have been crucial when it came to sightings.
"This wasn't in the day when there were thousands of selfies that could be used from Facebook."
Harper said the Blades episode would surprise many family, friends, police staff who had worked on the case and journalists who had written about it.
"We have all grown up believing we know everything about the case but I don't think we do."
Loper said he couldn't reveal too many details but said it was worthwhile reviewing the case.
"We have turned this investigation on its head, looking for avenues of inquiry which may not have been considered at the time. The team discusses the case in detail, questioning original information and the alternatives.
"We then set about gleaning further information from the file in the hope of formulating other avenues of inquiry and possible witnesses," Loper said.
Retired police officer Stewart Guy, from the original inquiry team, worked on the new investigation.
"As a family man and a police officer, I shudder to think. It would be a parent's worst nightmare. It's not something that ever leaves you. It certainly hasn't for me anyway."
The show will screen on TV 1 at 8.30pm. The other three cases to come in the Cold Case television series include Do Trieu from 2008, Kayo Matsuzawa from 1998 and Tuitania Barclay from 2002.
