Taieri College principal David Hunter said the pupil posted a threatening image on Snapchat, and while the boy thought it was funny at the time, police did not.
He said police arrived at the school about 8.30am, in search of the pupil.
"The lad thought it was a funny thing to do, but he’s not thinking that now.
"He was as white as a ghost when he walked into my office with a couple of police officers waiting for him.
"He’s come to the very quick realisation that once you press ‘send’ on Snapchat or Instagram or any social media account, it can have a whole lot of ramifications which he is aware of now.
"Once it’s on social media, it goes like wildfire.
"It was just a very poor choice from the young man, and he knows that now."
No-one was injured or in danger at any time.
Mr Hunter said no charges had been laid yet, but police would be following it up and the school was yet to decide on how it would deal with the issue.
He was very impressed with the rapid response from police.
"It’s encouraging that they’re keeping an eye out for that sort of behaviour."
A police spokeswoman declined to give details about what was in the "suspicious" online image, for fear of copycat behaviour.
"Police have spoken to the young person who allegedly posted the image and there is no cause for concern."
john.lewis@odt.co.nz
