The boy, a student at Spyken high school (gymnasiet), was taken by authorities at 6am Thursday morning, although the interrogation had yet to commence as of 9.30am, according to Skåne police spokesperson Mikael Persson.
In his threat, the boy referred to Wednesday’s school shooting in Germany.
The school’s principal, Karin Stavne, said the boy’s actions have sparked concern across the school community.
“There are a lot of people who are really scared. They’ve been calling all night long; they’ve been calling this morning. I tell them what I know, but I’m sure there are some who are so worried that they’ll stay at home anyway,” she told the TT news agency.
“We’re on hand with a crisis group who can speak with students and personnel, and then we’ll see what kind of activity we’ll have.”
It was a journalist from the Metro newspaper who late Wednesday night alerted police to the website with the boy’s threat.
The page has since been removed, but police have saved a copy, according to the Kvällsposten newspaper.
The website featured an image of the boy with a gun.
When police entered the boy’s home they found an air pellet gun, according to Skåne police homepage.