Years later, a man surfaced to Reddit, claiming to have known the guy behind the incident. He stated that the man, who was either a childhood friend or lived in his neighborhood had a hijacked radio and suffered from autism. The individual (like some people with autism) was described as being socially awkward and often talking/mumbling to himself (usually commercial jingles, TV theme songs or really random offensive things). This individual though has been disproven or cleared.
Another alleged suspect is the late artist Eric Fournier aka Shaye Saint John, who was an early YouTube star who died in 2010 and was about 19 at the time of the incident and did not live in or near Chicago.