There was a hasty article in the (Peoria Journal Star) PJStar this morning; they interviewed additional witnesses that confirmed the group size, but their accounts deny any racial comments. The additional witnesses also don't seem to indicate the same level of aggressiveness/violence.
Due to the timing (friday night), my coworker is convinced that it was just a rowdy party group.
PJStar also interviewed police and council. One council woman knew the one witness who claimed racial violence. Her statement was this guy is known for being a crank (my paraphrase).
When the police arrived the group scattered, and there are no reports of property damage.
My conclusion:
Probably a rowdy crowd, maybe party related. With no property damage and no serious threat, its not really actionable. The blog entry was based off the one witness, and is probably exaggerated.