Conversation so far:
What did Nas do at Virginia Tech ?
On September 6, 2007, Nas performed at a free concert for the Virginia Tech student body and faculty, following the school shooting there.
How was Bill O'Reilly involved ?
When announced that Nas was to perform, political commentator Bill O'Reilly and Fox News denounced the concert and called for Nas's removal
Was Nas arrested at Virginia Tech?
Nas was not arrested.

Question: What did he do that was controversial ?
Self-contained rewrite: What did Nas do that was controversial ?