Fire officials said they are "aggressively investigating" at Monday afternoon, and they're asking the public for help.
investigation is in cooperation with the and school officials, according to Salem Fire Capt. Al Dionne.
There were no injuries in the bathroom fires that were first reported at 1:14 p.m., according to Salem Police reports.
Deputy Chief Gerry Giunta of the Salem Fie Department said the person who first discovered a fire ran to the principal's office, and an alarm was pulled.
"The school was evacuated very quickly and efficiently," Giunta explained.
Giunta said the fires in the first and second floor bathrooms were concentrated in metal trash barrels.
On the third floor, Giunta said, there was paper on top of a toilet.
"The toilet roll itself actually burned," Giunta explained.
The deputy said there wasn't much damage — "one toilet seat was a little scorched."
The Salem Fire Department spent the majority of its time on scene ventilating smoke from the building after the fires were extinguished, according to scanner reports.
Anyone with any information is asked to call the Salem Fire Department at 978-744-1236.