Sycamore High School returned to a normal school day Wednesday after only about one-third of students attended Tuesday following a threat of violence against the school.

Following the threat found Sunday, only 439 of the 1138 students returned to school Tuesday. Classes were not held Monday for Casimir Pulaski Day.

Dr. Wayne Riesen, superintendant of Sycamore School District 427, said the majority of students were in school Wednesday and described the day as a “normal school day.”

Sunday, at a Sycamore business, a threat of violence against the school for Tuesday was found by an employee. The threat did not go into specifics about how the violence would take place, but did say it would take place at Sycamore High school and on Tuesday’s date.

Additional security presence on Tuesday continued Wednesday. Backpacks and bags were searched and students could only exit and enter through the main doors.

Uniformed police officers were stationed at locations inside and outside the school, including officers in plain clothes throughout the building.

Riesen said the district will be looking at changing security procedures in the future for all district schools in light of the threat.

“I think you’re going to see increased levels of security at all Sycamore schools in the future,” he said.

No one has claimed credit for the threat and no new information was available Wednesday about the threat.

“It’s an ongoing police matter,” Riesen said.

Sgt. Steve Cook of the Sycamore Police Department said the threat is still under investigation and the police are following up on some leads and examining evidence.

“We treat all threats like they are credible threats,” Cook said.