In Pakistan, extremist Sunis with ties to Al Qaeda are often killing Shhia or Izmaili Muslims. They want to start a sectarian civil war to destabilize the government.
Whenever someone is murdered, the other side goes on the rampage and kills some usually innocent person from the other religion.
If this was a religious killing, the smart thing is to let the police handle it and not "take the law into our own hands (become terrorists) like the criminals. We have good police and courts. They will handle it.
Al Qaeda would like to see riots which kill Muslims in America. This would give them good propaganda. Keep your powder dry. American Muslims are mostly middle-class people who have fled the craziness at home. They don't like terrorism. Al Qaeda would like to radicalize these people by making them the targets of violence.
Let the law do its job. Mob violence is terrorism.
Here is a description of the funeral.
http://www.nytimes.com/2005/01/18/nyregion/18jersey.html
Some Muslim leaders came and were welcomed by the Coptic priest, but some of the Christians were very angry and a fight started.
Please note that the Coptic priest kissed the Muslim Imam; they seem to be friends.
I know that CAIR has issues; at the same time, some people in these organizations are sincere and not trying to manipulate the organization for terrorism.
At Free Republic, people often ask, "Why don't the Muslims denounce terrorism?" The Muslims who came to this funeral did, but some Christians didn't accept it.