Zion police said they responded to a reported shooting in the school's parking lot during a basketball game against Waukegan.
Officers on a nearby patrol arrived and found two cars damaged, with the suspects fleeing the scene, police said.
No one was reported shot and police are investigating. Police said the Zion Fire Department was asked to evaluate a person who was injured while being inadvertently tramped.
The school district said classes would resume as normal Wednesday and that , " We will continue to work with appropriate authorities. As a precautionary measure we will have an increased police presence, start our day on code yellow, and ensure emotional support services for students and staff. As always, we take all matters seriously as the safety of our school community is our top priority."