Lawrence police officers and detectives are continuing their investigation into a written bomb threat that led to canceled classes Thursday at Free State High School.

The threat had been taped to the front door at the school, 4700 Overland Drive. It was found early Thursday morning. Administrators canceled classes and evacuated the building shortly before 8 a.m., then worked with district leaders and police to be sure no explosives were in the building.

Free State classes resumed Friday, as police continued to work with district personnel to seek the person or people responsible for the crime.

“We are taking this very seriously, because it affects the safety of our schools, staff and our children,” Sgt. Matt Sarna said.

Anyone with information regarding the threat may provide police with tips through the Crime Stoppers hotline, which is 785-843-TIPS (8477). Crime Stoppers does not subscribe to caller ID, and information leading to an arrest can result in a $1,000 reward.

Information also may be reported to the police department, at 785-832-7650.