On March 29, 1980, an unidentified 14-year-old boy was killed and eight others injured when two roller coaster trains collided.
Slivko killed his first victim, an unidentified homeless boy he estimated to be around 15 years old, in 1964.
The unidentified boy suffered first- and second-degree burns on the left side of this head and upper body.
The unidentified boy, who saw one of the three men pull a gun, tried to flee, the police said.
The Boone County Board of Education took the action against the unidentified boys after hearings on March 1 and 2, school officials said.
An unidentified 11-year-old boy also received a minor cut to his shin.
An unidentified 9-year-old boy and a 22-year-old man sitting in a private car nearby were seriously wounded.
Two of the passengers, Orlando Villanueva, address unknown, and the unidentified boy were wounded, the police said.
On September 4, 2006, an unidentified 11-year-old boy was injured when a stray .22 caliber bullet struck him in the wrist.