A suspicious fire in the boiler room at Central Junior High School is being investigated by local and state fire officials.

Lawrence-Douglas County Fire & Medical investigators wouldn’t label the fire an arson, but Lawrence public school officials are calling it a “criminal act.”

Students and staff at Central Junior High School were sent home with a letter assuring them that their safety was not compromised by a fire last week.

Monday morning, a janitor discovered the remnants of a fire, and school officials called in Lawrence Police and Lawrence-Douglas County Fire & Medical.

The Kansas Fire Marshal’s office also is assisting in the investigation, as is routine for a fire occurring in a public building.

It still was unclear late Monday exactly what was burned, Fire & Medical Deputy Chief Mark Bradford said.

There was no sign of a break-in at the school, which had been closed since Wednesday because of bad weather. The fire occurred after the school closed Tuesday and before it reopened Monday morning.

The fire burned itself out after causing minimal damage, Bradford said.

“We don’t feel the safety of students and staff was compromised in any way,” Central Principal Ted Juneau wrote in a letter distributed to staff and students to take home to their parents.

The school was searched after the discovery of the fire and no safety concerns were found, Juneau said.

The fire at Central, 1400 Mass., was the second suspicious school fire in less than two months. Christmas night, fire destroyed a mobile classroom at Hillcrest School, 1045 Hilltop Drive. Fire investigators have described the blaze as a possible arson. That investigation continues, Bradford said.

There is nothing to indicate the two school fires are related, Bradford said.

Anyone with information about the fires can call the Crime Stoppers hot line at 843-8477 (TIPS). Callers remain anonymous.