The rise of homegrown jihadists such as Dzhokhar Tsarnaev, condemned to death for his role in the Boston Marathon bombing, has caught counter-terrorism analysts off guard.

“What’s puzzling is that Tsarnaev was hardly an observant Muslim” said Peter Bergen, CNN’s national security analyst. In fact, Tsarnaev’s tweets had almost nothing to say about the practice of Islam and were typical for a 19-year-old American student interested in “sex, girls, marijuana and alcohol.”