That is the conundrum in the case of Norway and Anders Behring Breivik, who is being called a "Christian extremist" or "Christian terrorist."
As Westerners wrestle with such characterizations of the Oslo mass murder suspect, the question arises: Nearly a decade after 9/11 created a widespread suspicion of Muslims based on the actions of a fanatical few, is this what it's like to walk a mile in the shoes of stereotype?
"Absolutely," said Mark Kelly Tyler, pastor of Mother Bethel African Methodist Episcopal Church in Philadelphia. "It clearly puts us in a position where we can't simply say that extreme and violent behavior associated with a religious belief is somehow restricted to Muslim extremists."
During the first reports that someone had detonated a car bomb and then opened fire at a youth camp in Norway, many assumptions clicked into place.
"In all likelihood the attack was launched by part of the jihadist hydra," Thomas Joscelyn, a senior fellow at the Foundation for Defense of Democracies, wrote within hours on the Weekly Standard website.
The massacre was actually committed, police say, by a blond Norwegian. As Breivik's 1,500-page manifesto emerged, calling for violence to rid Europe of non-Christians and those he deemed traitors to Christian Europe, some seized on the religious aspect of his delusions.
Mark Juergensmeyer, editor of the book "Global Religions: An Introduction" and a sociology professor at UC Santa Barbara, wrote an essay likening Breivik to Timothy McVeigh, the American who killed 168 people in the 1995 Oklahoma City bombing. It was the deadliest terrorist attack on U.S. soil until 9/11.
McVeigh and Breivik were both "good-looking young Caucasians, self-enlisted soldiers in an imagined cosmic war to save Christendom, and both were Christian terrorists," Juergensmeyer wrote.
In a column for Salon.com, Alex Pareene said Breivik is not an American-style evangelical, but he listed other connections to Christianity. "All of this says 'Christian terrorist,' " Pareene wrote.
Such claims drew strong resistance. "Breivik is not a Christian. That's impossible. No one believing in Jesus commits mass murder," Bill O'Reilly said on his Fox News show.
That makes sense to Joyce Dubensky, CEO of the Tanenbaum Center for Interreligious Understanding. She said it also makes sense that "millions of Muslims say Osama bin Laden is not a Muslim, that no one who believes in the prophet Muhammad commits mass murder."
"We need to hear Bill O'Reilly, but we also need to hear and understand the voices of the overwhelming Muslim majority around the world who condemn those who are terrorists in the name of their faith," she said.
Arsalan Iftikhar, an international human rights lawyer and author of the upcoming book "Islamic Pacifism: Global Muslims in the Post-Osama Era," said the Norway attacks "proved that terrorism can be committed by a person of any race, nationality or religion."