The campus paper has a follow-up report, with quotes from national officials of Sigma Chi, Beta Theta Pi, Alpha Delta Pi, and Tau Kappa Epsilon:
http://www.dailyillini.com/news/camp...ond-to-arrests
The quotes seem to indicate a belief that most of the arrests involed individuals acting as individuals, and not problems widespread through a chapter.
I can only imagine how much fun it must be toward the end of the academic year to have national HQ investigating a chapter.