Officials say a police officer working at Dixon High School shot and wounded a former student who fired a gun at him.
There is a debate over school resource officers/armed guards at schools.
Students and staff at the high school responded "extremely well" to the situation, Howell said, adding that the district has received police department training on how to respond to shooters.
The police officer then returned fire and struck the man.
Federal and state officials also responded to the scene in Dixon, about 100 miles west of Chicago.
In regard to the students and teachers, Simonton said they were prepared and that they did exactly what we asked them to do. The shooter fired at the officer several times.
"While pursuing the suspect, the suspect shot several rounds toward the officer", Howell said. While all Dixon public school were put on lockdown earlier in the day, only Dixon High School remains on lockdown. The officer, whose name was not released by police, is on paid administrative leave, per policy, police said. He says the gunman is in custody with non-life-threatening injuries.
Authorities had not yet released the identity of the suspect, who was undergoing medical treatment for minor injuries.
Howell praised the school resource officer, saying he "could not be more proud" of him. "Because of his heroic actions, countless lives were saved". Authorities did not believe there was a further threat, and think the suspect acted alone, though the investigation was ongoing. "We are forever indebted to him for his service and his bravery".
"From the angle I'm looking at right now, a lot of things went right when a great many of them could have gone wrong", Dixon Mayor Li Arellano Jr. said at a news conference Wednesday.
When police searched the school they found that the faculty and students had barricaded themselves inside by blocking the classroom doorways with desks, chairs and other furniture - just as they had been trained to do.