The Disappearance of Mona Blades

Mona Elizabeth Blades was 18 and living in Hamilton when she decided to travel home to Hastings over Queen's Birthday weekend in 1975. She planned the surprise trip for a young nephew's birthday. Early on Saturday 31 May, her brother-in-law dropped her near Cambridge Road so she could hitchhike south. She never reached Hastings.

The orange Datsun sighting

Witness evidence placed Mona getting into an orange Datsun station wagon at about 10 a.m. Later that morning, a fencing contractor reported seeing a similar car parked on Matea Road, a side road off the Napier–Taupō highway. He saw a young woman matching Mona's description in the rear of the vehicle and a middle-aged man in the driver's seat. When he passed again, the car was empty.

The vehicle and its driver became central to the investigation, but police were never able to turn the sighting into evidence identifying a perpetrator.

A major search with no physical evidence

New Zealand Police describe the original inquiry as one of the country's largest manhunts. Officers spent six months and roughly 5,000 hours on the search and investigated more than 500 suspects. Despite that effort, they found no physical evidence and did not locate Mona's body.

The absence of a crime scene, remains or forensic evidence has left investigators dependent on witness recollections, vehicle information and later tips. No one has been prosecuted in connection with her disappearance.

Cold-case reviews

Police conducted a major review beginning in 2004 and have revisited the file again through their Cold Case programme. Investigators have reassessed the original photographs and witness accounts, including concern that the image of Mona distributed in 1975 may not have reflected how she looked on the day she vanished.

NZHistory records that the reinvestigation was wound down in 2006, but the case remains open. Police continue to invite information that could explain what happened to Mona or identify the vehicle and person associated with the last reported sightings.

Disappearance versus proven homicide

Mona's case is often described as one of New Zealand's longest unsolved murders, and investigators have long suspected she was killed. Her body, however, has never been found and no person has been convicted. For that reason, this file preserves the legal distinction: Mona is a missing person whose disappearance is investigated in a suspected-homicide context.