Gary Berntsen, fmr. CIA officer and author of author of "Jawbreaker," weighs in on the investigation into the Boston marathon bombings.
Berntsen explains why he's 'convinced' that Tamerlan and Dzhokhar Tsarnaev would have had training to produce the bombs used at the marathon attack.
"I'm convinced that they had training," Berntsen says. "I've had training myself when I was in the agency, and when I went through special operations training. That was probably 15-20 hours of hands-on, one-on-one to build those devices. If you look at many of the big bombers around the world...all of them had accidents when they were doing this stuff."
"This was complicated...I'm certain that he [one of the Tsarnaev brothers] had training," Berntsen reiterates.