Khalid Sheikh Mohammed, accused as the mastermind of al-Qaida's Sept. 11, 2001, attacks on the United States, has agreed to plead guilty, the Defense Department said Wednesday.

On Wednesday, the United States government announced that it had reached a plea deal with Khalid Sheikh Mohammed—the accused principal architect of the 9/11 attacks—and two alleged co ...

WASHINGTON — Khalid Sheikh Mohammed, accused as the main plotter in al-Qaeda’s Sept. 11, 2001, attacks on the United States, has agreed to plead guilty, the Defense Department said Wednesday ...