Facebook has proved a good way to locate missing people and solve crimes.
When 16-year-old Samantha Scott disappeared from her Child, Youth and Family home in Napier on May 18, police were at a loss to find her.
The popular and friendly teen left no clues to her location and extensive inquiries with friends, family and her school turned up nothing.
The police learned she was originally from Otorohanga and still had links to the area, so they asked Constable Ben Parsonage to post her photograph and information on the official Otorohanga Police Facebook page.
Within 24 hours she was found.
"We had more than 215,000 views of that post, we made a huge number of contacts, even Samantha's father in Australia saw it," said Mr Parsonage, who manages the page.
"It was then that everyone could see what a useful tool Facebook had become for New Zealand Police.
"Historically we would have relied on mainstream media, but Facebook means we can speak directly to the younger generation of people and that is something we have struggled with in the past."
Samantha's story is one of several cases of social media aiding police and emergency services.
Michael Shane Hagger, 34, became known as "Mr Hoorah" when he taunted Taupo police on their Facebook page while trying to evade capture.
The message gained attention on Twitter and Hagger handed himself in.
Thames Police also manage a Facebook page to great effect.
Facebook allowed police to "turn gossip into fact" and gather intelligence and witnesses, Mr Parsonage said.
"We have 1200 people who ‘like' our page but what we post goes out to all those peoples' friends as well, and that is 250,000 people.
"That is hugely beneficial."
The Facebook page is watched 24 hours a day,meaning police can gather more intelligence and solve crimes, he said.
"If an incident occurs in the Otorohanga region or the wider Waikato and we need to try and do a bit of a witness trawl, we can put the information we need them (witnesses) to give back to us onto our Facebook page.
"We have had seven or eight search warrants based on information via Facebook because people don't have to post publicly, I get and read all the private messages sent to the page."
There had been initial scepticism about Facebook's merits, he said.
"Definitely at the start there was a period of trying to convince people Facebook is a useful and practical police tool. A lot of older guys are old school but now they are the ones saying to me: ‘Can you put that on Facebook?'
"They are now well aware that Facebook increases the profile of a particular incident."
Michael Shane Hagger, 34, became known as "Mr Hoorah" when he taunted Taupo police on their Facebook page while trying to evade capture. The message gained considerable attention on Twitter and Hagger eventually handed himself in. Homicide detectives attached to Operation Olive, investigating the killing of Paeroa pizza shop owner Jordan Voudouris, have set up a Facebook page dedicated to the case. A Facebook page dedicated to the Rae Portman killing was set up. A man has now been charged with her killing.