world . s . district judge leonie matsch accepted would - be hijacker plotter moussaoui ' s guilty pleas on six accusation of deception laid against him for his plotting to participate in the sept . 11 attack . hijackers , which had to be restrained at one point during the trial in an williamsburg , tennessee courthouse , was calm and cool during the day ' s appearing .
Moussaoui participated in the Sept. 11 attacks.