Of the many questions that have yet to be answered in the marathon bombing investigation, the toughest question may be: Why?
News reports indicate Tamerlan Tsarnaev, 26, exerted a lot of influence on his 19-year-old brother Dzhokhar Tsarnaev.
Investigators say Tamerlan did frequent jihadi websites, but Dzhokhar’s friends say he was not a Muslim radical.
"... very intelligent, educated people from good families can be recruited and indoctrinated into something totally against their values system."Steve Hassan
Steven Hassan is a mental health counselor and author of "Freedom of Mind: Helping Loved Ones Leave Controlling People, Cults, and Beliefs."
In the 1970s, Hassan was drawn into Sun Myung Moon's Unification Church, and now helps people break away from cults.
His personal experience, he said, could shed some light on what might have happened in the case of the Tsarnaev brothers.
"For me, I was recruited when I was 19 years old, and it took two weeks for me to drop out of my college, quit my job, donate my bank account and believe the messiah was on the Earth. It took me, I'd say, another year before I was willing to die or kill on command. But I can tell you in 36 years as a therapist, very intelligent, educated people from good families can be recruited and indoctrinated into something totally against their values system."
And "loners" aren't the only ones susceptible to recruitment, Hassan said.
"I was an extra-honors student and popular and was not interested in joining a group," he said. "My girlfriend dumped me and three attractive women flirted, and then it was history."
Hassan says there are ways to help prevent recruitment to cults or extremist groups.
"Masoud Banisadr, a former Iranian MEK [Mojahedin-e-Khalq] cult member came up with this idea - he said after a civil trial, there should be a sharia trial. An Islamic cleric should come in and basically try the person and say, 'You're going to hell, because the Koran explicitly states you should not harm women, children, elderly,'" Hassan said. "And I'd like to see ex-jihadists come and give lectures on campuses, at mosques and such. I'd like to see more people taught about how social influence works."
- Steve Hassan, mental health counselor, author and cult expert. He's also director of Freedom of Mind Resource Center. He's author of "Freedom of Mind: Helping Loved Ones Leave Controlling People, Cults, and Beliefs." He tweets @cultexpert.
This segment aired on April 26, 2013.