Honolulu police investigators are looking for a possible connection between fires at two Waipahu schools, both arson, within three days.

"We’re looking into that but we haven’t made a determination," police Lt. Lisa Mann said.

Mann said police have no known suspects at either fire at Honowai Elementary and Waipahu Intermediate schools. The damage estimate is $240,000.

Mann said both fires started from outside the classrooms, and investigators were still determining how they began.

She said there was no graffiti or theft associated with the blazes.

The schools are about 1.1 miles apart in the western part of Waipahu.

The fire at Waipahu Intermediate School broke out at around 12:38 a.m. Friday, and at Honowai Elementary at about 9:15 p.m. Sunday.

Honowai Principal Kent Matsumura said the last fire at the school occurred about 16 years ago.

Matsumura said no summer classes were being taught at the affected classroom, although classes were taking place at other nearby buildings.

Damage to the classroom totaled $20,000 to the structure and $20,000 to its contents, fire officials said.

Matsumura, whose school has an enrollment of about 840 students from kindergarten to sixth grade, said losing the use of the classroom will add to its difficulties.

"Like any other school, we’re pressed for space," he said.

Waipahu Intermediate Principal Randell Dunn said the fire that destroyed a portable classroom has had a big impact on the school because of the loss of many computers, including 10 laptops.

"Kids in our community — some of them don’t have computers at home. For their families it’s a luxury," Dunn said.

Dunn said the portable building served as a classroom for a special-education resource science class, although no classes were being taught this summer.

He said the school serves about 1,200 students from the seventh through eighth grades, and the portable was built in 1998.

Dunn said he recalled a fire burning a door at the cafeteria and rubbish bins but nothing as major as the one Friday morning.