Mohammed Atef was a senior al-Qaeda military chief and top deputy to Osama bin Laden. According to The 9/11 Commission Report, bin Laden decided to give the green light to the Sept. 11 plot at Atef's urging. Atef was killed in a U.S. air strike on his home near Kabul in November 2001.
The Accused 9/11 Plotters: What Happened to Them?
News that self-confessed 9/11 mastermind Khalid Sheikh Mohammed and four other alleged 9/11 plotters are to be tried in New York will re-focus attention on the 2001 terrorist attacks. TIME takes a look at some of the men alleged to have plotted and carried out the strikes