A fire gutted a dormitory at Taru Girls' High School in Kinango constituency, Kwale, on Wednesday.
County commissioner Mr Karuku Ngumo said the cause of the fire, that destroyed all the property in the facility, was not established immediately.
But he added that investigations were launched after a "suspicious material" was found in the facility.
The incident took place as students attended morning preps. The institution has a total of 260 students.
"It was reported by the principal that at around 7 am, they noticed smoke coming out of the dormitory," Mr Ngumo said, adding all the learners are safe but lack an alternative.
He urged all school managers and security agencies in the county to be alert so such cases are prevented.