Florentia, as a Springfield area native, born and raised, I would like to offer my two cents....generally speaking, this area isn't what I would consider "the bad part of town". Also, Kickapoo High School isn't what I would consider "the low income school" either. That said, even the high class, big fancy house neighborhoods can have people living there who are up to no good....same as the best high schools in the country may have students who are up to no good.
I know that's kind of vague, but I was 6 in 1992 and nobody else has chimed in. For the most part, Springfield was really quiet in 1992. Was there drugs and crime....sure. But three people disappearing, never to be seen again was unthinkable. That's why this was, and still is, so big in Springfield. At the time, this was something that blew the whole town away!
My opinion only....I still live a couple miles NW of town, I would be happy to help satisfy curiosity any way I can, just send a pm if you like.