The stolen ceremonial key to Wellington's Town Hall has been handed back to the city's mayor today by police after it was returned by the thief.
The small gold and pounamu key, worth $8000, was taken from its display case at the Museum of Wellington City and Sea nearly a week ago.
A local lawyer contacted Wellington police yesterday and said he had been given the key by an anonymous person to give back to the city, police said.
Outside the Town Hall, Wellington Mayor Celia Wade-Brown said whoever took the key must have realised it could not be disposed of easily.
"We take our role as guardians of artifacts seriously -- whether it's the chains, whether it's a key -- and we're delighted it has been returned unharmed."
The key would be stored at the city archives until security arrangements had been made at the museum to return it, she said.
Wellington Museums Trust chief executive Pat Stuart said she did not expect to have the key returned.
"So I believe that whoever did take it, once they realised the impact it was having and the significance of the item, [chose to return it]."
The museum would be making adjustments to its security, especially around an upgrade for one of the cameras.
"We're very pleased to have it back, it felt like a personal theft from our point of view, we were devastated."
Wellington police Area Commander Inspector Chris Scahill said the most important thing was to have the key returned safely in its original condition.
"Having said that, our investigation remains open and we obviously encourage anybody who may know any of the circumstances surrounding the original theft of the key to come forward to police."
Staff at the museum noticed the key had been taken last Thursday, police spokesman Nick Bohm said.
The sealed case had been prised open with a sharp object and the key taken sometime in the 24 hours before the theft was noticed.
The 110-year-old key was presented to Wellington's mayor at the time, John Aitken, by jeweller Frank Grady at the opening of the Town Hall on December 14, 1904.
"Symbolic" keys to the city have since been presented to deserving people.
The next in line for the honour is cricketer Brendon McCullum for his record-breaking triple century for New Zealand against India at the city's Basin Reserve ground in February.
A date was yet to be set for the event.
It would be the first time the mayor had offered the ceremonial keys to the city since 2002, when Lord of the Rings' director Sir Peter Jackson and scriptwriter Fran Walsh accepted their keys, along with Weta Workshop's Richard Taylor and Tania Rodger.