The boy suspected in the case had been searched for in recent days, including by helicopter and by the Home Guard, but was found around 12 noon on Wednesday.
During the afternoon, the police confirmed that he is suspected of being behind the threat to the school environment.
After questioning, prosecutors decided to arrest the boy as a reasonable suspect - the lower level of suspicion - on suspicion of aggravated unlawful threats against a group.
Police are not saying whether the boy has any connection to either school.
“I choose not to comment on it,” police spokesman Mats Öhman told TT earlier.
The incident is being investigated as a serious unlawful threat against a group.
One school is closed.
The municipality has decided to open schools as usual on Thursday, saying the police have assessed that the threat situation is no longer present.
An independent elementary school, however, has chosen to remain closed on Thursday as well, writes Borlänge Tidning. The principal says they have received a threat against the school and are therefore closing as a precaution.
The police confirm that a separate threat was received against a school in Borlänge in the early afternoon, without saying which school it was.
“But that threat has been deemed frivolous after investigative measures,” Mats Öhman told TT on Wednesday evening.
The incident will be investigated, but as a false alarm and an illegal threat.
“Cannot be underestimated”
The closed schools affected thousands of students in Borlänge on Wednesday, both municipal preschools and primary and secondary schools. A number of independent schools also made their own decisions to close.
“When it comes to the threats, they cannot be downplayed or minimized,” Municipal Director Jörgen Olsson said at a press conference earlier in the day.
The police took the threats very seriously, Deputy Area Chief Jimmy Spolander said.
“We will not go into what the threat is about, but it is a threat to school operations and a threat of serious crime.”
The background is that information was spread among students already on Monday, which raised concerns. On Tuesday evening, municipal employees received information.
