A fire that caused heavy smoke damage to the boys' bathroom of Kootenai Junior High on Wednesday is being investigated as arson.

"It's definitely arson — there's no question," Kootenai School District Superintendent Lynette Ferguson said today.

She said students are being interviewed by school district staff. No citations or arrests have been made. There were no injuries.

Ferguson said evidence was found that points to arson, but she couldn't elaborate, citing the pending investigation. 

Ferguson said the Kootenai County Sheriff's Office plans to interview students on Monday.

The building was evacuated on Wednesday and students were dismissed at 1:15 p.m. School resumed as normal today as crews clean up the damage.

Ferguson said most of the damage was contained to the bathroom and adjacent hallway.

"A student reported to a teacher the smoke coming from the bathroom," she said. "Within 5 minutes, the halls were filled with black smoke."

Students from the junior high and Harrison Elementary went to the high school as a precaution before being dismissed for the day.

Ferguson said the district's maintenance supervisor put out the fire with an extinguisher. Fire crews from St. Maries and the volunteer Harrison Fire Department responded.