Today's bomb hoax won't be the last time schools are threatened, a security expert warns.
Thousands of students across New Zealand were forced to evacuate their classrooms after pre-recorded bomb threats were delivered over the phone.
The Herald can confirm schools in Auckland, Hamilton, Tauranga, Gisborne, Palmerston North, Masterton and Christchurch received calls.
It is the second time bomb threats have terrorised students this year. In February, at least 33 schools received bomb hoax phone calls.
Security expert Dr Paul Buchanan said threats against children were meant to instil fear in the community, usually as revenge.
If the same person was behind the two incidents, Buchanan believed today's threats won't be the last.
"If they're not caught then they are emboldened.
"If you did it once and stopped, well this is a person who's having a really bad day. Now that he's done it twice, that's terroristic intent."
Police said they would not be disclosing the names of each school that had received a call today, given the ongoing investigation and to prevent further such calls being made to other schools.
They believed that today's calls may be similar to those received earlier this year, which inquiries indicated originated overseas.
Similar threats have been made in the United States, and more recently in Australia.
Buchanan, who emphasised he hasn't been part of the investigation so can only speculate, explained there was a stark difference between a threat that contained an ideological message and one that didn't.
A political message indicated someone was more likely to follow up with a real act of violence, he said.
"If there isn't any ideological message then you get into the realm of someone who's mentally ill, who gets their jollies from scaring families and schools."
Buchanan doubted Isis had an involvement in the bomb scare. He said the Islamic terror group was under siege and had less capability than even six months ago.
"It's not coming from Daesh [Isis].
"It would take them time and considerable effort to get the phone numbers of these schools when they have so many other targets that are easier to go after."
Buchanan believed the perpetrator was probably a man, as they were responsible for the majority of threats like this. He also felt the offender was more likely to be in New Zealand.
The motive could be anything from someone's cat being run over by a school bus, racism, an expulsion, or losing a school board of trustees election, he said.
Buchanan would be more worried about the risk of violence if the threat was delivered in an automated voice. He said if they were tech-savvy enough to do that, it was likely they would know how to find online bomb manuals.
"If you can do that your capability to do harm will increase."
Buchanan urged police to release the transcript of the message so security experts like him can provide insights. He said the perpetrator will know the police are investigating anyway.
"It's a double-edged sword, if you don't give the public any leads then people like me can't offer you any insights.
"On the other hand if you keep it to yourself you might be able to take this guy quietly.
"This is a test for the police. Right now it's no longer funny."
When the Herald asked police if they will release the transcript they replied that they had nothing further to add to their earlier release and the investigation was ongoing.
Berkley Normal Middle School was among the schools evacuated, with students sent to wait outside in the rain.
Student Louis Knox, 12, sat on the field for two hours, taking cover under a tree to stay dry.
His mum Shannon McKenzie said he had no shoes on as kids weren't allowed back into the classroom.
Even though no violence has followed the threats Buchanan urged schools to continue to take them seriously.
"You can't do anything else. You're dealing with the lives of children."