When Palmerston North police knocked on the door of the office of the mayor, Heather Tanguay had no idea they were coming.

The knock happened in the middle of her campaign for re-election in 2007.

Heather and Jerry Tanguay have never spoken publicly about the events of that day.

Even in 2013 the experience strikes a raw nerve - it stings more than anything else in their 26 years in Palmerston North.

The police had arrived because they had caught the culprits repeatedly destroying her campaign signs.

The vandals were young and part of a youth group wing of a local church. One was a head student at a local school.

Police asked Heather if she wanted to prosecute them. She didn't, but demanded a face-to-face explanation and apology.

"We have to have a mayor that God can talk through," they told her.

"We were shattered by it," she says, tears streaming down her face. "It was a terrible experience."