Umar Farouk Abdulmutallab, here in Milan, Mich., was charged in federal court in December with trying to detonate an explosive device on a Dec. 25 flight from Amsterdam to Detroit. U.S. Marshals Service/AP hide caption

itoggle caption U.S. Marshals Service/AP

The building housing the San'a Institute for the Arabic Language in Yemen's capital, where Umar Farouk Abdulmutallab studied. Peter Kenyon/NPR hide caption

itoggle caption Peter Kenyon/NPR