Who goes missing?

Detective Sergeant Liam Clinton says, "the biggest missing person category belongs to those who 'voluntarily' disappear. This includes youth runaways and adults who purposely break contact with family and friends and don't want to be found.

Children and young people who abscond from CYFS facilities or foster homes are the second biggest category. Many of them are repeat absconders who go missing for one or two nights, and are usually quickly found."

Alerts in the new National Intelligence Application (NIA) system mean a missing CYFS person can be returned quickly to their residence.

Liam says work is ongoing with CYFS to improve processes for the reporting of missing CYFS residents.

Mental health patients are the third biggest category of missing people, many of whom are 'absent without leave' from scheduled appointments.

Fears for the patient's safety and the risk they pose to the public determine how quickly such patients are reported missing.

Interestingly, less than one percent of missing people are Kiwis reported missing overseas or foreign nationals missing in New Zealand.

Liam says in these situations his Unit takes a coordinating role, working closely with Interpol, NZ Customs, embassies, consulates and the Ministry of Foreign Affairs and Trade.

"Based on the missing person's known travel arrangements, we try and narrow their movements down," he says.

"But we can have inquiries going in two or three different places and tourists' plans can change without them advising anyone,"

When it comes to missing people, Liam says you never know what's going to solve the case further down the track.

Bones get washed up on the beach or dredged up in a fishing net; ice melts to reveal a climber's remains; hunters might discover the skeleton of a fellow hunter many years later; and people may be more prepared to talk about why someone disappeared long after the event.

"Time may not heal all wounds, but it can heal old wounds," Liam says. "We get a few nice stories occasionally."

He recalls a case not long after the Unit began when, following some publicity about the Unit, a mother reported her son missing. He'd gone to Australia nine years earlier and she'd had no contact with him. The Unit quickly found the son. In fact, he was back in New Zealand and living in the same city as his mother. However, he wanted no contact with her.

The last Liam heard of the case was that the son had sent his mum a Christmas card, perhaps the first step toward rebuliding any burnt bridges.

But there's also the other end of the scale where missing people can have such a devastating effect on family and friends.

Liam tells of a recent high-profile case where a New Zealand man was declared dead after an assumed suicide. His body was never found. But he showed up this year with a stolen identity, having lived a new life in the South Island for five years. Each year since disappearing, his family commemorated his death at the site of his faked suicide.

There's also a few tricks up the Missing Persons Unit's sleeve which can flush out those trying to remain missing, for whatever reason.

Liam says the hardest part of his job is not being able to give family more information or updates about their missing loved one.

"Sometimes 'I don't know' means 'I don't know' and this can be frustrating for everyone."

He says his most personally frustrating - but still active - case is that of a missing Blenheim man in a freezing forestry area in Russia.

"Coordinating an inquiry in a foreign country, with a language barrier and no real sense of the priority they're giving the case... you can understand the family's anger and angst."