Superintendent Mark Vollmer said it will cost more than $100,000 to clean and repair the new Erik Ramstad Middle School following two vandalism incidents last week.
The school district is offering a $5,000 reward for information leading to the arrest of the vandals, he said.
The vandals painted the band room in the building under construction in northwest Minot on Aug. 7. The following night, on Aug. 8, they set two fires on the first floor academic wing.
Vollmer said the fire caused no structural damage, but did leave a great deal of smoke damage.
"The cleaning company will be working around the construction," said Vollmer, who said the school is still scheduled to be completed by the Thanksgiving break. "We do not anticipate any delay."
Vollmer said he has increased security at the construction site in the meantime. The building is sealed and there are security personnel on duty at the site throughout the night. During the day, there are hundreds of construction workers on site.
Vollmer urged anyone with information about the school vandalism to contact the Minot Police Department.
The school district had insurance on the building.
The old Ramstad was destroyed in the flood of 2011. Classes for Ramstad students have been held in the Minot Municipal Auditorium for the past two years. Students will start classes in the auditorium later this month and move over to the new building after the Thanksgiving break.