CNN CNN Newsroom February 21, 2014 14:05:00
31-year-old college dropout, who one official says could be connected to the threat. here is what terrorism experts say. >> this has his signature all over it. this is just the kind of device he is trying to build and has built in the past. >> reporter: u.s. intelligence officials tell cnn he is the best bomb maker in any al qaeda affiliate. they believe he is working in the shadows, working with al qaeda in arabian peninsula, they say he designed the underwear bomb that failed to detonate at the last minute on a detroit bound plane in 2009. and it was his printer cartridge bombs which the fol...