Peter Bergen is CNN's national security analyst, a vice president at New America and a professor of practice at Arizona State University. He is the author of "United States of Jihad: Investigating America's Homegrown Terrorists." The opinions expressed in this commentary are his own. View more opinion articles at CNN.

(CNN) Sri Lankan Defense Minister Ruwan Wijewardene said Wednesday that most of the terrorists who killed at least 253 people at churches and hotels in Sri Lanka on Sunday were "well-educated and come from maybe middle- or upper-middle-class. So, they are financially quite independent, and their families are quite stable financially."

Peter Bergen

Two of the suicide bombers were the sons of a wealthy Sri Lankan spice trader, Mohamed Ibrahim, sources with knowledge of the investigation told CNN

This likely runs counter to what many people may believe about suicide bombers. After all, why would well educated, upper-middle-class folks with seemingly everything to live for blow themselves up and kill so many innocents?

Of course, there is no simple answer for what must be a difficult decision, nor is there a one-size-fits-all description of how people radicalize to the point that they are willing to die while killing.

In the case of Sunni militants, this decision is likely enabled by their embrace of violent jihadist ideology, which is often sectarian in nature and encourages the murder of "infidels." This is often combined with the belief that Sunni Muslims are under attack and revenge must be taken.