The schools were cordoned off and closed to the roughly 1,300 students after workers at the Heleneholm high school found the firearms. They uncovered one rifle with telescopic sight, one shotgun, and ammunition while working on the roof.
“It was pure coincidence,” Patrik Tullberg, a builder at the school, told the Expressen newspaper.
“You wonder whether someone has put them up there to collect them or to use them.”
Police closed the school for the entirety of Friday, and will remain present on Saturday.
“In a student environment, it’s especially important to be thorough,” Erik Jansäker of the local police told the TT news agency.
“We have decided that police will be on the scene for the weekend so that everyone in the area will feel safe.”
Police refused to comment on whether the weapon was believed to be linked to any crimes that had taken place in the area, nor whether there were any suspects.