A major legacy of Holder's tenure as attorney general was a shifting of terrorism cases to the civilian federal courts. Under Holder, the DOJ successfully tried many terrorists in federal court, securing convictions and life sentences against a string of defendants, including Sulaiman Abu Ghaith (Osama bin Laden's spokesman); Ahmed Ghailani (a conspirator in the 1998 East Africa bombings); and Abu Hamza (an al-Qaeda operative). Faisal Shahzad (the attempted Times Square bomber); and Omar Farouk Abdulmutallab (the failed "underwear bomber") pleaded guilty in federal court and were sentenced to life imprisonment during Holder's term. During Holder's term, other terrorists—including Najibullah Zazi (who plotted a New York subway attack), and Ahmed Abdulkadir Warsame (an al-Shabab supporter) pleaded guilty and cooperated with the government. Matt Olsen, the director of the National Counterterrorism Center from 2011 to 2014, wrote in 2015: "Through his persistence, Holder demonstrated the wisdom and value of prosecuting terrorists in civilian courts and cemented this approach for future administrations."