SILER CITY, N.C. — After three fires in two months damaged three Chatham County schools, community members, school officials and fire investigators have expressed concern over the unusual number of fires.

The school system rarely has had to deal with situations involving fire. None of the three recent ones occurred when students and staff were in school.

"We appreciate community members who are watchful of our school campuses with us," said Dr. Larry Mabe, superintendent of Chatham County Schools. "All of the fires have occurred at times when our campuses were unoccupied. Without the assistance of concerned individuals and the quick response of emergency services, the damage would undoubtedly have been worse."

On April 3, fire destroyed a mobile classroom unit at Perry Harrison School. A classroom at Pittsboro Elementary School then sustained fire damage on April 10. Last Sunday, there was a fire in the Ramsey school gymnasium.

Tom Bender, the Chatham County fire marshal, determined the Harrison fire to be electrical and said that the Pittsboro Elementary fire was deliberately set.

The Pittsboro Elementary fire continues to be under investigation by local law enforcement.

A replacement mobile unit arrived at Harrison before the school year ended. Repairs were completed at Pittsboro Elementary in time for the displaced class to return to it regular classroom.

The Ramsey fire damaged an area around a section of bleachers. After receiving results of samples tested from the burned region, Bender said the cause of the fire -- which started in a trash can -- was undetermined.

Chatham County Schools leases the gym to the town of Siler City for recreational use. The town recreation department is in charge of gym activities. The school system is working with insurance adjusters to establish the cost of the claim.